Cisco Voice/Fax Network Module
Contents
1. E Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module Configuration Tasks W Table 4 Troubleshooting Voice Port Configurations continued Problem Suggested Action Jerky or choppy speech Variable delay or jitter is being introduced by congestion in the packet network Two possible remedies are to e Reduce the amount of congestion in your packet network Pings between VoIP endpoints will give an idea of the round trip delay of a link which should never exceed 300 ms Also examine network queuing and dropped packets e Increase the size of the jitter buffer with the playout delay command See the Configuring Adaptive Jitter Adjustment section on page 20 Clipped or fuzzy speech Reduce input gain See the Configuring Voice Level Adjustment section on page 21 Clipped speech Reduce the input level at the listener s router See the Configuring Voice Level Adjustment section on page 21 Volume too low or missed DTMF Increase speaker s output level or listener s input level See the Configuring Voice Level Adjustment section on page 21 Echo interval is greater than 25 ms sounds like a separate voice Configure the echo cancel enable command and increase the value for the echo cancel coverage keyword See the Configuring Echo Adjustment section on page 21 Too much echo Voice Port Testing Comm2. Configuring Disconnect Supervision Commands section on page 14 and Configuring FXO Supervisory Disconnect Tone Commands section on page 16 for voice port commands that configure additional recognition of disconnect signaling In most cases the default voice port command values are sufficient to configure FXO and FXS voice ports Disconnect Supervision Commands PBX and PSTN switches use several different methods to indicate that a call should be disconnected because one or both parties have hung up The commands in this section are used to configure the router to recognize the type of signaling in use by the PBX or PSTN switch connected to the voice port These methods include the following e Battery reversal disconnect e Battery denial disconnect e Supervisory tone disconnect STD Battery reversal occurs when the connected switch changes the polarity of the line in indicate changes in call state such as off hook or in this case call disconnect This is the signaling looked for when the battery reversal command is enabled on the voice port which is the default configuration Battery denial sometimes called power denial occurs when the connected switch provides a short approximately 600 ms interruption of line power to indicate a change in call state This is the signaling looked for when the supervisory disconnect command is enabled on the voice port which is the default configuration Cisco IOS Release 12 2 2 XT a
3. No connectivity Enter the show voice port command with the voice port number that you are troubleshooting which will tell you e If the voice port is up If it is not use the no shutdown command to make it active e What parameter values have been set for the voice port including default values these do not appear in the output for the show running config command If these values do not match those of the telephony connection you are making reconfigure the voice port Telephony device buzzes or does not ring Use the show voice port command to confirm that ring frequency is configured correctly It must match the connected telephony equipment and may be country dependent Distorted speech Use the show voice port command to confirm that the cptone keyword setting also called region tone is US Music on hold is not heard Reduce the music threshold level Background noise is not heard Enable the comfort noise command Long pauses occur in conversation like speaking on a walkie talkie Overall delay is probably excessive the standard for adequate voice quality is 150 ms one way transit delay Measure delay by using ping tests at various times of the day with different network traffic loads If delay must be reduced areas to examine include propagation delay of signals between the sending and receiving endpoints voice encoding delay and the voice packetization time for various VoIP codecs
4. ring l tip ground disable and the keyword disable to end the forced state Note For each signaling type FXO FXS only the applicable keywords are displayed The disable keyword is displayed only when a relay is in the forced state Cisco IOS Release 12 2 2 XT and 12 2 8 T EEM Cisco High Density Analog Voice and Fax Network Module W Configuration Tasks Fax Voice Mode Tests The test voice port switch fax command forces a voice port into fax mode for testing After you enter this command you can use the show voice call or show voice call summary command to check whether the voice port is able to operate in fax mode If no fax data is detected by the voice port the voice port remains in fax mode for 30 seconds and then reverts automatically to voice mode The disable keyword ends the forced mode switch however the fax mode ends automatically after 30 seconds The disable keyword is available only while the voice port is in fax mode To force a voice port into fax mode and return it to voice mode use the following commands in privileged EXEC mode Command Purpose Step1 Router test voice port slot subunit port switch fax Identifies the voice port you want to test Enter the keyword fax to force the voice port into fax mode Step2 Router test voice port slot subunit port switch Identifies the voice port on which you want to end ateabie the test Enter the keyword disable to return the voice port to vo
5. conversation Once the delay exceeds 150 ms a conversation is more like a walkie talkie conversation in which one person must wait for the other to stop speaking before beginning to talk You can measure delay fairly easily by using ping tests at various times of the day with different network traffic loads If network delay is excessive it must be reduced for adequate voice quality Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module HI Feature Overview Several different types of delay combine to make up the total end to end delay associated with voice calls e Propagation delay Amount of time it takes the data to physically travel over the media e Handling delay Amount of time it takes to process data by adding headers taking samples forming packets and so on e Queuing delay Amount of time lost due to congestion e Variable delay or jitter Amount of time that causes the conversation to break and become unintelligible Jitter is described in detail below amp Note Propagation handling and queuing delay are not addressed by voice port commands and fall outside the scope of this document Voice Level Adjustment As much as possible it is desirable to achieve a uniform input decibel level to the packet voice network to limit or eliminate any voice distortion due to incorrect input and output decibel levels Adjustments to levels may be required b
6. Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module WE debug hpi debug hpi Syntax Description Defaults Command Modes Command History Usage Guidelines Examples Related Commands To enable debugging for Host Port Interface HPI message events use the debug hpi command in EXEC mode To reset the default value for this feature use the no form of this command debug hpi all command detail error notification response no debug hpi all command detail error notification response all Enables all HPI debug options command detail error notification and response command Displays commands being sent to the 54x DSP detail Displays additional detail for the HPI debugs enabled error Displays any HPI errors notification Displays notification messages sent from the 54x DSP for example tone detection notification response Displays responses to commands sent by the 54x DSP for example responses to statistic requests This command is not enabled EXEC Release Modification 12 1 5 XM This command was first introduced on the Cisco AS5300 and Cisco AS5800 12 2 2 T This command was implemented on the Cisco 1700 Cisco 2600 series Cisco 3600 series and the Cisco 3810 12 2 8 T This command was integrated into the Cisco IOS Release 12 2 8 T This command enables debugging for HPI message events wh
7. Platform 124XT 12 2487 Cisco 2600 series X X Cisco 3640 X X Cisco 3660 X X Supported Standards MIBs and RFCs Standards e No new or modified Standards are supported by this feature MIBs e No new or modified MIBs are supported by this feature To obtain lists of supported MIBs by platform and Cisco IOS release and to download MIB modules go to the Cisco MIB website on Cisco com at the following URL http www cisco com public sw center netmgmt cmtk mibs shtml RFCs e No new or modified RFCs are supported by this feature Prerequisites e Obtain analog line or analog trunk service from your PBX Key System or PSTN e Complete your company s dial plan e Establish a working telephony network based on your company s dial plan e Install at least one other network module or WAN interface card to provide the connection to the network LAN or WAN e Establish a working IP and Frame Relay or ATM network For more information about configuring IP refer to the Cisco IOS IP Configuration Guide Release 12 2 e Install appropriate voice processing and voice interface hardware on the router See the Configuring Analog FXO and FXS Voice Ports section on page 11 Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module Configuration Tasks W Configuration Tasks See the following sections for configuration tasks for this feature e Configuring Analog FXO and
8. changes the polarity of the line to indicate changes in call state such as off hook or in this case call disconnect This is the signaling looked for when the battery reversal command is enabled on the voice port which is the default configuration Battery denial sometimes called power denial occurs when the connected switch provides a short approximately 600 ms interruption of line power to indicate a change in call state This is the signaling looked for when the supervisory disconnect command is enabled on the voice port which is the default configuration Supervisory tone disconnect occurs when the connected switch provides a special tone to indicate a change in call state Some PBXs and PSTN CO switches provide a 600 millisecond interruption of line power as a supervisory disconnect and others provide supervisory tone disconnect STD This is the signal that the router is looking for when the no supervisory disconnect command is configured on the voice port Note In some circumstances you can use the FXO Disconnect Supervision feature to enable analog FXO ports to monitor call progress tones for disconnect supervision that are returned from a PBX or from the PSTN For more information see the Configuring FXO Supervisory Disconnect Tone Commands section on page 16 E Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module Configuration Tasks W To change parameters
9. density of analog interfaces provides voice and data over a single network 16 analog voice ports in a single network module NM e Connects existing analog voice telephone sets fax machines and key systems using Cisco gateways Scalability Modularity and Flexibility e Eliminates the need for a channel bank e The network module may be configured to be an FXO an FXS or a combination module Serviceability e Provides remote monitoring testing and diagnoses Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module HI Feature Overview Restrictions S Note The following features not supported at this time ATM SVC SAS signaling Supported High Complexity Codecs G 711 a law G 711 u law G 723 1 ANNEX A 5300 bps G 723 1 ANNEX A 6300 bps G 723 1 5300 bps G 723 1 6300 bps G 726 16000 bps G 726 24000 bps G 726 32000 bps G 728 16000 bps G 729 ANNEX B 8000 bps G 729 8000 bps GSMER 13200 bps Supported Medium Complexity Codecs G 726 16000 bps G 726 24000 bps G 726 32000 bps G 729 ANNEX B 8000 bps Annex A version G 729 8000 bps Annex A version Supported low Complexity Codecs G 711 a law 64000 bps G 711 u law 64000 bps Three way calling is not supported with low complexity codecs The ring capacity is 10 Ringer Equivalency Number REN The total of all RENs of the telephones connected to the one line must not exceed the value 5 o
10. digit signal duration The range of the pulse digit signal duration is from 10 to 20 The default is 20 Router config voiceport timing pulse interdigit FXO only Specifies pulse dialing interdigit timing in milliseconds Valid entries are from 100 to 1000 The default is 500 Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module W Configuration Tasks Voice Quality Tuning Commands The commands in this section configure parameters to improve voice quality Common voice quality issues include the following e Configuring Adaptive Jitter Adjustment optional e Configuring Echo Adjustment optional e Configuring Voice Level Adjustment optional Configuring Adaptive Jitter Adjustment To configure the playout delay jitter buffer use the following commands beginning in dial peer or voice port configuration mode Command Purpose Step1 Router config voiceport playout delay mode adaptive Determines the mode in which the jitter buffer will fixed operate for calls on this voice port The keywords are as follows e adaptive Adjusts the jitter buffer size and amount of playout delay during a call based on current network conditions e fixed Defines the jitter buffer size as fixed so that the playout delay does not adjust during a call A constant playout delay is added The default is adaptive Step 2 Router config voiceport pl
11. duration of the call Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module WE Glossary Cisco IOS Release 12 2 2 XT and 12 2 8 T
12. for voice port configuration voice port 1 0 0 signal loopStart no vad station id name test1 abc station id number 8000 caller id enable voice port 1 0 1 signal loopStart no vad voice port 1 0 2 signal loopStart no vad voice port 1 0 3 signal loopStart no vad I Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module Command Reference W Command Reference This section documents previously undocumented commands All other commands used with this feature are documented in the Cisco IOS Release 12 2 command reference publications e debug dspapi page 32 e debug hpi page 34 This section documents modified commands All other commands used with this feature are documented in the Cisco IOS Release 12 2 command reference publications e voice port page 35 Cisco IOS Release 12 2 2 XT and 12 2 8 T EEN Cisco High Density Analog Voice and Fax Network Module W debug dspapi debug dspapi To enable debugging for Digital Signal Processor DSP Application Programming Interface API message events use the debug dspapi command in EXEC mode To reset the default value for this feature use the no form of this command debug dspapi all command detail error notification response no debug dspapi all command detail error notification response Syntax Description all Enables all dspapi debug options command detai
13. letter locale for the voice call progress tones and other locale specific parameters to be used on this voice port Cisco routers comply with the ISO 3166 locale name standards To see valid choices enter a question mark following the eptone command The default is us Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module W Configuration Tasks Command Purpose Step4 Router config voiceport ring frequency 25 50 FXS only Selects the ring frequency in hertz HZ used on the FXS interface This number must match the connected telephony equipment and may be country dependent If not set properly the attached telephony device may not ring or it may buzz The keyword default is 25 on Cisco 2600 series Cisco 3640 and Cisco 3660 routers Step5 Router config voiceport ring number number FXO only Specifies the maximum number of rings to be detected before an incoming call is answered by the router The default is 1 Step6 Router config voiceport ring cadence pattern01 FXS only Specifies an existing pattern for ring or pattern02 pattern03 pattern04 pattern05 defines a new one Each pattern specifies a pattern06 pattern07 pattern08 pattern09 i ring pulse time and a ring interval time The pattern10 patternil patterni2 define pulse interval keywords and arguments are as follows e pattern01 through patt
14. only the applicable keywords are displayed The disable keyword is displayed only when a detector is in the forced state Step2 Router test voice port slot subunit port detector Identifies the voice port on which you want to end m lead battery reversal loop current ring the test Enter a keyword for the detector under tip ground ring ground ring trip disable test and the keyword disable to end the forced state Note For each signaling type FXO FXS only the applicable keywords are displayed The disable keyword is displayed only when a detector is in the forced state Loopback Function Tests To establish loopbacks on a voice port use the following commands in privileged EXEC mode Command Purpose Step1 Router test voice port slot subunit port loopback Identifies the voice port you want to test and enters local network a keyword for the loopback direction Note A call must be established on the voice port under test Step 2 Router test voice port slot subunit port loopback Identifies the voice port on which you want to end disable the test and enters the keyword disable to end the loopback Cisco IOS Release 12 2 2 XT and 12 2 8 T EJ l Cisco High Density Analog Voice and Fax Network Module Configuration Tasks W Tone Injection Tests To inject a test tone into a voice port use the following commands in privileged EXEC mode Command Purpose Step1 Router test vo
15. specific set of features and which features are supported in a specific Cisco IOS image You can search by feature or release Under the release section you can compare releases side by side to display both the features unique to each software release and the features in common To access Cisco Feature Navigator you must have an account on Cisco com If you have forgotten or lost your account information send a blank e mail to cco locksmith cisco com An automatic check will verify that your e mail address is registered with Cisco com If the check is successful account details with a new random password will be e mailed to you Qualified users can establish an account on Cisco com by following the directions at http www cisco com register Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur For the most current information go to the Cisco Feature Navigator home page at the following URL http www cisco com go fn Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module W Supported Standards MIBs and RFCs Table 2 lists the hardware platforms that support this feature and the releases in which the feature was first supported If the First T train Release column is blank the feature is not yet available in a Cisco IOS T release on that platform Table 2 Cisco IOS Release and Platform Support for this Feature
16. Cisco High Density Analog Voice and Fax Network Module Feature History Release Modification 12 2 2 XT These features were implemented on the Cisco 2600 series Cisco 3640 and the Cisco 3660 router 12 2 8 T This feature was integrated into Cisco IOS Release 12 2 8 T This document describes the Cisco High Density Analog Voice and Fax Network Module NM HDA in Cisco IOS Release 12 2 8 T This document includes the following sections e Feature Overview page 2 e Supported Platforms page 9 e Supported Standards MIBs and RFCs page 10 e Prerequisites page 10 e Configuration Tasks page 11 e Configuration Examples page 29 e Command Reference page 31 e Glossary page 37 Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module HI Feature Overview Feature Overview The Cisco High Density Analog Voice and Fax Network Module provides DTMF detection voice compression and decompression call progress tone generation voice activity detection VAD echo cancellation and adaptive jitter buffering for up to 16 ports The following port combinations are supported e Twelve Foreign Exchange Station FXS ports e Eight Foreign Exchange Office FXO ports and four FXS ports e Twelve FXS and four FXO ports e Four Foreign Exchange Station FXS ports The base card supports four FXS ports The addition of an eight port FXS expansion module can increase the capacity to tw
17. FXS Voice Ports required e Configuring Voice Activity Detection VAD optional e Fine Tuning Analog Voice Ports optional e Verifying Analog Voice Port Configurations optional Configuring Analog FXO and FXS Voice Ports To configure basic analog voice port parameters on Cisco 2600 series Cisco 3640 and Cisco 3660 routers use the following commands beginning in global configuration mode Command Purpose Step1 Router config voice port slot subunit port Enters voice port configuration mode The arguments are as follows e slot Specifies the number of the router slot where the voice network module is installed e port lIndicates the voice port See Table 1 on page 2 for valid entries e subunit Specifies the location of the Cisco High Density Analog Voice Fax Netwo tk Module NM HDA The valid entry is 0 Note A slash must be entered between arguments Valid entries vary by router platform enter the show voice port summary command for available values Step2 FXO or FXS Selects the access signaling type to match that of Router config voiceport signal loop start the telephony connection you are making The ground start keywords are as follows e loop start default Uses a closed circuit to indicate off hook status used for residential loops e ground start Uses ground and current detectors preferred for PBXs and trunks Step3 Router config voiceport eptone locale Selects the two
18. To configure a voice port to detect incoming tones you must know the parameters of the tones expected from the PBX or PSTN Then create a voice class that defines the tone detection parameters and finally apply the voice class to the applicable analog FXO voice ports This procedure configures the voice port to go on hook when it detects the specified tones The parameters of the tones need to be precisely specified to prevent unwanted disconnects due to detection of nonsupervisory tones or noise A supervisory disconnect tone is normally a dual tone consisting of two frequencies however tones of only one frequency can also be detected Use caution if you configure voice ports to detect nondual tones because unwanted disconnects can result from detection of random tone frequencies You can configure a voice port to detect a tone with one on off time cycle or you can configure it to detect tones in a cadence pattern with up to four on off time cycles Delay in Voice Networks Delay is the time it takes for voice packets to travel between two endpoints Excessive delay can cause quality problems with real time traffic such as voice However because of the speed of network links and the processing power of intermediate devices some delay is expected When listening to speech the human ear normally accepts up to about 150 ms of delay without noticing delays The ITU G 114 standard recommends no more than 150 ms of one way delay for a normal voice
19. a removal of line power Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module W Configuration Tasks Configuring FXO Supervisory Disconnect Tone Commands To create a voice class that defines the specific tone or tones to be detected and then apply the voice class to the voice port use the following commands beginning in global configuration mode Command Purpose Step1 Router config voice class dualtone tag Creates a voice class for defining one tone detection pattern The range for the tag number is from 1 to 10000 The tag number must be unique on the router Step2 Router config voice class freq pair tone id Specifies the two frequencies in Hz for a tone to frequency 1 frequency 2 be detected or one frequency if a nondual tone is to be detected If the tone to be detected contains only one frequency enter 0 for frequency 2 The arguments are as follows e tone id Ranges from 1 to 16 There is no default e frequency I and frequency 2 Ranges from 300 to 3600 or you can enter 0 for frequency 2 There is no default Note Repeat this command for each additional tone to be specified Step3 Router config voice class freq max deviation Specifies the maximum frequency deviation that TreJUSDEY will be detected in Hz The frequency argument ranges from 10 to 125 The default is 10 Step4 Router config voice class freq max power dBmO Speci
20. ands Reduce the output level at the speaker s voice port See the Configuring Voice Level Adjustment section on page 21 These commands allow you to force voice ports into specific states for testing They require the use of Cisco IOS Release 12 0 7 XK or 12 1 2 T or a later release and they apply to Cisco 2600 series Cisco 3640 and Cisco 3660 routers The following types of voice port tests are covered e Detector Related Function Tests optional e Loopback Function Tests optional e Tone Injection Tests optional e Relay Related Function Tests optional e Fax Voice Mode Tests optional Cisco IOS Release 12 2 2 XT and 12 2 8 T ic Cisco High Density Analog Voice and Fax Network Module W Configuration Tasks Detector Related Function Tests Using the test voice port detector command you are able to force a particular detector into an on or off state perform tests on the detector and then return the detector to its original state To configure this feature use the following commands in privileged EXEC mode Command Purpose Step 1 Router test voice port slot subunit port detector Identifies the voice port you want to test Enter a m lead battery reversal loop current ring keyword for the detector under test and specify tip d ing d ing tri ff ip ground ring ground ring trip on off whether to force it to the on or off state Note For each signaling type FXO FXS
21. aptive jitter buffering adaptive jitter buffer intelligently balances delay and packet loss through the gateway for maximum call clarity and quality CAS Channel Associated signaling A signaling technique that uses the same facility path for both voice and signaling traffic comfort noise generation While using VAD the DSP at the destination emulates background noise from the source side preventing the perception that a call is disconnected DSP Digital Signal Processor Specialized microprocessor used for voice processing DTMF dual tone multifrequency Tones used to send phone number digits to and from a switch DTMF tones identify the number 0 9 and the and symbols ground start Used for PBX and other services that must have ground signal to indicate when a dial tone is applied by the serving switching system or is used to avoid glare Advantages of Ground Start minimizes the possibility of glare provides Far End Disconnect Supervision for example the remote user can disconnect and local FXO can be made aware of this and also disconnect H 323 ITU T standard for multimedia logical channels NM HDA High Density Analog Voice and Fax Network Module immediate start In the immediate start protocol the originating side does not wait for a wink before sending addressing information After receiving addressing digits the terminating side then goes off hook for the duration of the call The originating endpoint main
22. as introduced 11 3 3 T Support for Cisco 2600 series routers was added 12 0 3 T Support for the Cisco AS5300 access server was added 12 0 7 T Support for the Cisco AS5800 universal access server the Cisco 7200 series router and the Cisco 1750 router was added Arguments for the Cisco 2600 series and Cisco 3600 series router were added 12 2 2 XT This command was modified on the Cisco 2600 series the Cisco 3640 series and the Cisco 3660 series to accommodate the additional ports of the NM HDA 12 2 8 T This command was integrated into the Cisco IOS Release 12 2 8 T Use the voice port command in global configuration mode to switch to voice port configuration mode from global configuration mode Use the exit command to exit voice port configuration mode and return to global configuration mode The following example accesses voice port configuration mode for port 0 located on subunit 0 on a voice interface card installed in slot 1 for the Cisco 3660 series voice port 1 0 0 Cisco IOS Release 12 2 2 XT and 12 2 8 T ic Cisco High Density Analog Voice and Fax Network Module WE voice port Related Commands Command Description dial peer voice Enters dial peer configuration mode and specifies the method of voice encapsulation Cisco IOS Release 12 2 2 XT and 12 2 8 T 36 sO l Cisco High Density Analog Voice and Fax Network Module Glossary Glossary W ATM Asynchronous Transport Mode ad
23. atus which signals the CO to provide dial tone An incoming call is signaled from the CO to the handset by sending a signal in a standard on off pattern which causes the telephone to ring Loop start has two disadvantages however that usually are not a problem on residential telephones but that become significant with the higher call volume experienced on business telephones Loop start signaling has no means of preventing two sides from seizing the same line simultaneously a condition known as glare Also loop start signaling does not provide switch side disconnect supervision for FXO calls The telephony switch the connection in the PSTN another PBX or key system expects the router s FXO interface which looks like a telephone to the switch to hang up the calls it receives through its FXO port However this function is not built into the router for received calls it only operates for calls originating from the FXO port Another access signaling method used by FXO and FXS interfaces to indicate on hook or off hook status to the CO is ground start signaling It works by using ground and current detectors that allow the network to indicate off hook or seizure of an incoming call independent of the ringing signal and allow for positive recognition of connects and disconnects For this reason ground start signaling is typically used on trunk lines between PBXs and in businesses where call volume on loop start lines can result in glare See the
24. ayout delay nominal value Tunes the playout buffer to accommodate packet maximum value minimum default low high jitter caused by switches in the WAN The keywords and arguments are as follows e nominal Defines the amount of playout delay applied at the beginning of a call by the jitter buffer in the gateway In fixed mode this is also the maximum size of the jitter buffer throughout the call e value Specifies the range that depends on type of DSP and configured codec complexity For medium codec complexity the range is from 0 to 150 ms For high codec complexity and DSPs that do not support codec complexity the range is from 0 to 250 ms e maximum adaptive mode only Specifies the jitter buffer s upper limit 80 ms or the highest value to which the adaptive delay is set e minimum adaptive mode only Specifies the jitter buffer s lower limit 10 ms or the lowest value to which the adaptive delay is set e default Specifies 40 ms Cisco IOS Release 12 2 2 XT and 12 2 8 T 20 l Cisco High Density Analog Voice and Fax Network Module Configuring Echo Adjustment Step 1 Step 2 Step 3 Configuration Tasks W By design echo cancellers are limited by the total amount of time they wait for the reflected speech to be received which is known as an echo trail The echo trail is normally 32 milliseconds In Cisco System voice implementations echo cancellers are enabled using the ec
25. e of the interface increasing or decreasing the signal After an input gain setting is changed the voice call must be disconnected and reestablished before the changes take effect The value argument is any integer from 6 to 14 The default is 0 Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module W Configuration Tasks Command Purpose Step2 Router config voiceport output attenuation value Specifies the amount of attenuation in decibels at the transmit side of the interface decreasing the signal A system wide loss plan can be implemented using the input gain and output attenuation commands The default value for this command assumes that a standard transmission loss plan is in effect meaning that normally there must be 6 dB attenuation between phones The value argument is any integer from 6 to 14 The default is 0 Step3 Router config voiceport impedance 600r complex1 Specifies the terminating impedance of a voice port interface which needs to match the specifications from the specific telephony system to which it is connected e 600r Specifies 600 ohms real e complex1 Specifies Complex 1 The default is 600r Verifying Analog Voice Port Configurations Step 1 Step 2 Step 3 Step 4 Step 5 After configuring the voice ports on your router perform the following steps to verify proper operation Pick up t
26. e the debug voip ccapi error EXEC command To enable debugging on all virtual voice port module VPM areas use the debug vpm all command To turn off all port level debugging use the no debug vpm all command It is usually a good idea to turn off all debugging and then enter the debug commands you are interested in one by one This will help to avoid confusion about which ports you are actually debugging To show messages from the digital signal processor DSP on the V Fast Class VFC modem to the router use the debug vtsp dsp EXEC command Cisco IOS Release 12 2 2 XT and 12 2 8 T ic Cisco High Density Analog Voice and Fax Network Module W Configuration Tasks To troubleshoot specific areas of the high density analog network module perform the following steps e To show messages from the DSP on the VPM to the router Use the debug vpm dsp e To show which debug commands are enabled use the show debug e To enable the display of trunk conditioning supervisory component trace information use the debug vtsp all Troubleshooting Chart Table 4 lists some problems you might encounter after configuring voice ports and some suggested remedies Table 4 Problem Troubleshooting Voice Port Configurations Suggested Action No connectivity Ping the associated IP address to confirm connectivity If you cannot successfully ping your destination refer to the Cisco IOS IP Configuration Guide Release 12 2
27. elve FXS ports The addition of two four port FXO expansion modules can increase the capacity to eight FXO ports and four FXS ports The addition of one each of the FXS and FXO expansion modules can increase the capacity to twelve FXS ports and four FXO ports The FXO expansion module supports a power failure port which connects directly to the central office CO in case of failure The digital signal processors DSPs on the network module support up to eight ports of high complexity codecs or up to sixteen ports of medium complexity and low complexity codecs The number of DSPs must be increased if more than eight ports of high complexity codecs are needed In this case a DSP expansion module must be installed Table 1 shows analog voice port numbering which differs for each of the voice enabled routers More current information may be available in the release notes that accompany the Cisco IOS software you are using Table 1 High Density Analog Voice Port Numbering Base Module Telephony Signaling Voice Port Numbers Interface NM HDA 4FXS FXS 0to3 EMO FXO 4to7 EMO FXS 4to 11 EM1 FXO 14 to 17 EM1 FXS 14 to 21 A Caution No more than a total of 12 FXS ports can be configured at one time Cisco IOS Release 12 2 2 XT and 12 2 8 T aa l Cisco High Density Analog Voice and Fax Network Module Feature Overview Ml Telephony Signaling Interfaces Voice ports on routers and access servers phys
28. ern12 name pre set ring cadence patterns Enter ring cadence to see ring pattern explanations e define pulse interval specifies a user defined pattern pulse is a number one or two digits from 1 to 50 specifying ring pulse on time in hundreds of milliseconds and interval is a number one or two digits from to 50 specifying ring interval off time in hundreds of milliseconds The default is the pattern specified by the cptone locale that has been configured Step7 Router config voiceport description string Attaches a text string to the configuration that describes the connection for this voice port This description appears in various displays and is useful for tracking the purpose or use of the voice port The string argument is a character string from 1 to 255 characters in length The default is that there is no text string describing the voice port attached to the configuration Step8 Router config voiceport no shutdown Activates the voice port If a voice port is not being used shut the voice port down with the shutdown command Cisco IOS Release 12 2 2 XT and 12 2 8 T 42 l Cisco High Density Analog Voice and Fax Network Module Configuration Tasks W Configuring Voice Activity Detection VAD Step 1 Step 2 Command Voice activity detection VAD is configured on dial peers by default it is enabled For more information see the Configuring Dial Plans Dial Peers and Di
29. fies the maximum tone power that will be detected in dBmO The dBmO argument ranges from 0 to 20 The default is 10 Step5 Router config voice class freq min power dBmO Specifies the minimum tone power that will be detected in dBmO The dBmO argument ranges from 10 to 35 The default is 30 Step6 Router config voice class freq power twist dBmO Specifies the power difference allowed between the two frequencies in dBmO The dBmO argument ranges from 0 to 15 The default is 6 Step7 Router config voice class freq max delay time Specifies the timing difference allowed between the two frequencies in 10 millisecond increments The time argument ranges from 10 to 100 100 ms to 1 sec The default is 20 200 ms Step 8 Router config voice class cadence min on time time Specifies the minimum tone on time that will be detected in 10 millisecond increments The time argument ranges from 0 to 100 0 ms to 1 sec Step 9 Router config voice class cadence max off time time Specifies the maximum tone off time that will be detected in 10 millisecond increments The time argument ranges from 0 to 5000 0 ms to 50 sec Cisco IOS Release 12 2 2 XT and 12 2 8 T 16 l Cisco High Density Analog Voice and Fax Network Module Command Configuration Tasks Purpose Step10 Router config voice class cadence list cadence id cycle 1l on time cycle 1 off time cycle 2 on time cycle 2 off time cycle 3
30. git Manipulation chapter in the Cisco IOS Release 12 2 Voice Video and Fax Configuration Guide Release 12 2 Two parameters associated with VAD music threshold and comfort noise are configured on voice ports If VAD is enabled use the following commands to adjust parameter values associated with VAD beginning in voice port configuration mode Purpose Router config voiceport music threshold number Specifies the minimal decibel level of music played when calls are put on hold The decibel level affects how voice activity detection VAD treats the music data Valid entries range from 70 to 30 When used with VAD if the level is set too high the remote end hears no music if it is set too low there is unnecessary voice traffic The default is 38 Router config voiceport comfort noise This parameter creates subtle background noise to fill silent gaps during calls when VAD is enabled on voice dial peers If comfort noise is not generated the resulting silence can fool the caller into thinking the call is disconnected instead of being merely idle The default is that comfort noise is enabled Fine Tuning Analog Voice Ports amp Normally default parameter values for voice ports are sufficient for most networks Depending on the specifics of your particular network however you may need to adjust certain parameters that are configured on voice ports Collectively these commands are referred to as vo
31. gured on the gateway playout delay should be configured in dial peer configuration mode When there are numerous dial peers to configure it might be simpler to configure playout delay on a voice port If there are conflicting playout delay configurations on a voice port and also on a dial peer the dial peer configuration takes precedence Voice Activity Detection Commands Benefits In normal voice conversations only one person speaks at a time Today s circuit switched telephone networks dedicate a bidirectional 64 kbps channel for the duration of each conversation regardless of whether anyone is speaking at the moment This means that in a normal voice conversation at least 50 percent of the bandwidth is wasted when one or both parties are silent This figure can actually be much higher when normal pauses and breaks in conversation are taken into account Packet switched voice networks on the other hand can use this wasted bandwidth for other purposes when voice activity detection VAD is configured VAD works by detecting the magnitude of speech in decibels and deciding when to cut off the voice from being framed VAD has some technological problems however which include the following e General difficulties in determining when speech ends e Clipped speech when VAD is slow to detect that speech is beginning again e Automatic disabling of VAD when conversations take place in noisy surroundings Cost Effective e Higher
32. he handset of an attached telephony device and check for a dial tone If you have dial tone check for DTMF detection If the dial tone stops when you dial a digit then the voice port is most likely configured properly To identify port numbers of voice interfaces installed in your router use the show voice port summary command For examples of the output see the Analog FXS Voice Port Example section on page 30 To verify voice port parameter settings use the show voice port command with the appropriate syntax from Table 3 For sample output see the Analog FXO Voice Port Example section on page 29 Table 3 Show Analog Voice Port Command Syntax Platform Command Syntax Cisco 2600 series show voice port slot number subunit number port Cisco 3640 Cisco 3660 To display voice channel configuration information for all DSP channels use the show voice dsp command Router show voice dsp Cisco IOS Release 12 2 2 XT and 12 2 8 T i 2 l Cisco High Density Analog Voice and Fax Network Module Configuration Tasks W Step6 To verify the call status for all voice ports use the show voice call summary command Router show voice call summary Step7 To display the contents of the active call table which shows all of the calls currently connected through the router or concentrator use the show call active voice command Router show call active voice Step8 To display the contents of the call history
33. ho cancel enable command and echo trails are configured using the echo cancel coverage command To configure parameters related to the echo canceller use the following commands beginning in voice port configuration mode Command Purpose Router config voiceport echo cancel enable Enables the cancellation of voice that is sent and received on the same interface Echo cancellation coverage must also be configured The default is that echo cancellation is enabled Router config voiceport echo cancel coverage 8 16 24 32 Adjusts the echo canceller by the specified number of milliseconds The default is 16 Router config voiceport non linear Enables nonlinear processing residual echo suppression in the echo canceller which shuts off any signal if no near end speech is detected Echo cancelling must be enabled for this feature The default is that nonlinear processing is enabled Configuring Voice Level Adjustment Step 1 Use the input gain and output attenuation commands to adjust voice levels and the impedance command to set the impedance value to match that of the voice circuit to which the voice port connects To change parameters related to voice levels use the following commands as appropriate in voice port configuration mode Command Purpose Router config voiceport input gain value Specifies in decibels the amount of gain to be inserted at the receiver sid
34. ically connect the router or access server to telephony devices such as telephones fax machines PBXs and PSTN central office CO switches These devices may use any of several types of signaling interfaces to generate information about on hook status ringing and line seizure The router s voice port hardware and software must be configured to transmit and receive the same type of signaling being used by the device with which they are interfacing so that calls can be exchanged smoothly between the packet network and the circuit switched network The signaling interfaces discussed in this document include foreign exchange office FXO and foreign exchange station FXS which are types of analog interfaces It is important to know which signaling method the telephony side of the connection is using and to match the router configuration and voice interface hardware to that signaling method The next three illustrations show how the different signaling interfaces are associated with different uses of voice ports In Figure 1 FXS signaling is used for end user telephony equipment such as a telephone or fax machine Figure 2 shows an FXS connection to a telephone and an FXO connection to the PSTN at the far side of a WAN this might be a telephone at a local office going over a WAN to a router at headquarters that connects to the PSTN Figure 1 FXS Signaling Interfaces Voice port Serial or Serial or Voice port 1 0 0 Ethernet port Ethernet po
35. ice mode Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module Configuration Examples W Configuration Examples This section provides the following voice port configuration examples e Analog FXO Voice Port Example e Analog FXS Voice Port Example Analog FXO Voice Port Example The following example shows analog FXO output for voice port configuration voice port 1 0 4 no vad timeouts call disconnect 3 timeouts wait release 3 connection trunk 8004 answer mode supervisory disconnect dualtone pre connect supervisory answer dualtone no battery reversal voice port 1 0 5 no vad timeouts call disconnect 3 timeouts wait release 3 connection trunk 8005 answer mode supervisory disconnect dualtone pre connect supervisory answer dualtone no battery reversal voice port 1 0 6 no vad timeouts call disconnect 3 timeouts wait release 3 connection trunk 8006 answer mode supervisory disconnect dualtone pre connect supervisory answer dualtone no battery reversal voice port 1 0 7 no vad timeouts call disconnect 3 timeouts wait release 3 connection trunk 8007 answer mode supervisory disconnect dualtone pre connect supervisory answer dualtone no battery reversal Cisco IOS Release 12 2 2 XT and 12 2 8 T ic Cisco High Density Analog Voice and Fax Network Module Configuration Examples Analog FXS Voice Port Example The following example shows analog FXS output
36. ice port slot subunit port inject tone Identifies the voice port you want to test and enters local network 1000hz 2000hz 200hz 3000hz keywords for the direction to send the test tone and 30012 320012 340012 edna saute for the frequency of the test tone Note A call must be established on the voice port under test Step 2 Router test voice port slot subunit port inject tone Identifies the voice port on which you want to end disable the test and enters the keyword disable to end the test tone Note The disable keyword is available only if a test condition is already activated Relay Related Function Tests To test relay related functions on a voice port use the following commands in privileged EXEC mode Command Purpose Step1 Router test voice port slot subunit port relay Identifies the voice port you want to test Enter a e lead loop ring ground battery reversal keyword for the relay under test and specify denial i tip d ff i power denial ring tip ground on off whether to force it to the on or off state Note For each signaling type FXO FXS only the applicable keywords are displayed The disable keyword is displayed only when a relay is in the forced state Step2 Router test voice port slot subunit port relay Identifies the voice port on which you want to end e ey xing ground Fae nae the test Enter a keyword for the relay under test BERNA tibe poyer denial
37. ice port tuning commands Note The commands keywords and arguments that you are able to use may differ slightly from those presented here based on your platform Cisco IOS release and configuration When in doubt use Cisco IOS command help command to determine the syntax choices that are available The voice port tuning commands are grouped into these categories and explained in the following sections e Configuring Disconnect Supervision Commands optional e Configuring FXO Supervisory Disconnect Tone Commands optional e Configuring Timeouts Commands optional e Timing Commands optional e Voice Quality Tuning Commands optional Full descriptions of the commands in this section can be found in the Cisco IOS Voice Video and Fax Command Reference Release 12 2 Cisco IOS Release 12 2 2 XT and 12 2 8 T ic Cisco High Density Analog Voice and Fax Network Module W Configuration Tasks Configuring Disconnect Supervision Commands PBX and PSTN switches use several different methods to indicate that a call should be disconnected because one or both parties have hung up The commands in this section are used to configure the router to recognize the type of signaling in use by the PBX or PSTN switch connected to the voice port These methods include the following e Battery reversal disconnect e Battery denial disconnect e Supervisory tone disconnect STD Battery reversal occurs when the connected switch
38. ich are used to communicate with the 54x DSPs This command severely impacts performance and should be used only for single call debug capture The following example shows how to enable debugging for all HPI message events Router debug hpi all Command Description debug dspapi Enables debugging for DSP API message events Cisco IOS Release 12 2 2 XT and 12 2 8 T BE l Cisco High Density Analog Voice and Fax Network Module voice port Syntax Description Defaults Command Modes Command History Usage Guidelines Examples voice port W To enter voice port configuration mode use the voice port command in global configuration mode Cisco 2600 and Cisco 3600 Router voice port slot number subunit number port slot number Slot number in the Cisco router in which the High Density Analog Voice and Fax Network Module NM HDA is installed Valid entries are from 0 to 3 depending on the slot in which it has been installed subunit number Subunit on the NM HDA in which the voice port is located Valid entry is 0 port Voice port number Valid entries are 0 to 21 slot The router location in which the voice port adapter is installed Valid entries are from 0 to 3 port e Indicates the voice interface card location Valid entries are 0 to 21 See Table 1 on page 2 for port numbering No default behavior or values Global configuration Release Modification 11 3 1 T This command w
39. ing the entire call e pre connect Specifies tone detection only during call setup Step 15 Router config voiceport supervisory disconnect anytone Configures the voice port to disconnect on receipt of any tone Cisco IOS Release 12 2 2 XT and 12 2 8 T ica Cisco High Density Analog Voice and Fax Network Module W Configuration Tasks Configuring Timeouts Commands To change timeouts parameters use the following commands as appropriate in voice port configuration mode Command Purpose Step1 Router config voiceport timeouts call disconnect Configures the call disconnect timeout value in seconds seconds Valid entries range from 0 to 120 The default is 60 Step2 Router config voiceport timeouts initial seconds Sets the number of seconds that the system waits between the caller input of the initial digit and the subsequent digit of the dialed string If the wait time expires before the destination is identified a tone sounds and the call ends The seconds argument is the initial timeout duration A valid entry is an integer from 0 to 120 The default is 10 Step 3 Router config voiceport timeouts interdigit seconds Configures the number of seconds that the system waits after the caller has input the initial digit or a subsequent digit of the dialed string If the timeout ends before the destination is identified a tone sounds and the call ends This value is important when using va
40. l error notification and response command Displays commands sent to the DSPs detail Displays additional detail for the dspapi debugs enabled error Displays any dspapi errors notification Displays notification messages sent from the DSP for example tone detection notification response Displays responses sent by the DSP for example responses to statistic requests Defaults This command is not enabled Command Modes EXEC Command History _ Release Modification 12 1 5 XM This command was first introduced on the Cisco AS5300 and Cisco AS5800 12 1 5 XM1 This command was implemented on the Cisco AS 5350 and Cisco AS5400 12 2 2 T This command was implemented on the Cisco 1700 Cisco 2600 series Cisco 3600 series and the Cisco 3810 12 2 8 T This command was integrated into the Cisco IOS Release 12 2 8 T Usage Guidelines _ DSP API message events used to communicate with DSPs are intended for use with Connexant Nextport and Texas Instrument 54x DSPs This command severely impacts performance and should be used only for single call debug capture Examples The following example shows how to enable debugging for all DSP API message events Router debug dspapi all Cisco IOS Release 12 2 2 XT and 12 2 8 T BEJ l Cisco High Density Analog Voice and Fax Network Module debug dspapi W Related Commands Command Description debug hpi Enables debugging for Host Port Interface HPI message events
41. n voice port configuration mode Command Purpose Router config voiceport milliseconds timing dial pulse min delay Specifies time in milliseconds between the generation of wink like pulses when the type is pulse Valid entries are from 0 to 5000 The default is 300 for the Cisco 3600 series routers Router config voiceport timing digit milliseconds Specifies the DTMF digit signal duration in milliseconds Valid entries are from 50 to 100 The default is 100 Router config voiceport milliseconds timing guard out FXO ports only Specifies the duration in milliseconds of the guard out period that prevents this port from seizing a remote FXS port before the remote port detects a disconnect signal The range is from 300 to 3000 The default is 2000 Router config voiceport milliseconds timing hookflash out Specifies the duration in milliseconds of the hookflash Valid entries are from 50 to 500 The default is 300 Router config voiceport timing interdigit Specifies the DTMF interdigit duration in milliseconds milliseconds Valid entries are from 50 to 500 The default is 100 Router config voiceport timing pulse FXO only Specifies the pulse dialing rate in pulses per second pulses per second Valid entries are from 10 to 20 The default is 20 Router config voiceport milliseconds timing pulse digit FXO only Configures the pulse
42. nd 12 2 8 T 4 l Cisco High Density Analog Voice and Fax Network Module Feature Overview Ml Supervisory tone disconnect occurs when the connected switch provides a special tone to indicate a change in call state Some PBXs and PSTN CO switches provide a 600 millisecond interruption of line power as a supervisory disconnect and others provide supervisory tone disconnect STD This is the signal that the router is looking for when the no supervisory disconnect command is configured on the voice port Note In some circumstances you can use the FXO Disconnect Supervision feature to enable analog FXO ports to monitor call progress tones for disconnect supervision that are returned from a PBX or from the PSTN For more information see the Configuring FXO Supervisory Disconnect Tone Commands section on page 16 FXO Supervisory Disconnect Tone Commands Note If the FXO supervisory disconnect tone is configured and a detectable tone from the PSTN or PBX is detected by the Digital Signal Processor DSP the analog FXO port goes on hook This feature prevents an analog FXO port from remaining in an off hook state after an incoming call is ended FXO supervisory disconnect tone enables interoperability with PSTN and PBX systems whether or not they transmit supervisory tones This feature applies only to analog FXO ports with loop start signaling on the Cisco 2600 series the Cisco 3640 and the Cisco 3660 routers
43. on time cycle 3 off time cycle 4 on time cycle 4 off time Optional Specifies a tone cadence pattern to be detected Specify an on time and off time for each cycle of the cadence pattern The arguments are as follows e cadence id Ranges from to 10 There is no default e cycle N on time and cycle N off time Range from 0 to 1000 0 ms to 10 sec The default is 0 Step 11 Router config voice class cadence variation time Optional Specifies the maximum time that the tone onset can vary from the specified onset time and still be detected in 10 millisecond increments The time argument ranges from 0 to 200 0 ms to 2 sec The default is 0 Step 12 Router config voice class exit Exits voice class configuration mode Step 13 Router config voice port slot subunit port Enters voice port configuration mode The arguments are as follows e slot Specifies the slot number where the voice network module is installed e subunit Specifies the Cisco High Density Analog Voice Fax Netwo rk Module NM HDA where the voice port is located e port lIdentifies the analog voice port number See Table 1 on page 2 for valid entries Router config voiceport supervisory disconnect dualtone mid call pre connect voice class tag Step 14 Assigns an FXO supervisory disconnect tone voice class to the voice port The keywords are as follows e mid call Specifies tone detection dur
44. r some or all of the ringers may not operate Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module Supported Platforms W Related Documents For information about installing voice network modules and voice interface cards in Cisco 2600 series Cisco 3640 and Cisco 3660 routers see these publications e Cisco 2600 Series Hardware Installation Guide e Cisco 3620 and Cisco 3640 Modular Access Routers Quick Start Guide e Cisco 3600 Series Hardware Installation Guide e Update to the Cisco Network Module Hardware Installation Guide e WAN Interface Card Hardware Installation Guide For information about configuring Voice features see these publications e Cisco 2600 Series Software Configuration Guide e Cisco IOS Release 12 2 Voice Video and Fax Configuration Guide e Cisco IOS Release 12 2 Voice Video and Fax Command Reference Guide Supported Platforms e Cisco 2600 series e Cisco 3640 e Cisco 3660 Determining Platform Support Through Cisco Feature Navigator Cisco IOS software is packaged in feature sets that support specific platforms To get updated information regarding platform support for this feature access Cisco Feature Navigator Cisco Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature Cisco Feature Navigator is a web based tool that enables you to quickly determine which Cisco IOS software images support a
45. related to disconnect supervision use the following commands as appropriate in voice port configuration mode Command Purpose Step1 Router config voiceport battery reversal Enables battery reversal The default is that battery reversal is enabled e For FXO ports Use the no battery reversal command to configure a loop start voice port to not disconnect when it detects a second battery reversal The default is to disconnect when a second battery reversal is detected Note Also use the no battery reversal command when a connected FXO port does not support battery reversal detection e For FXS ports Use the no battery reversal command to configure the voice port not to reverse battery when it connects calls The default is to reverse battery when a call is connected then return to normal when the call is over providing positive disconnect See also the disconnect ack command Step 7 Step2 Router config voiceport supervisory disconnect FXO only Enables the PBX or PSTN switch to provide STD By default the supervisory disconnect command is enabled Step3 Router config voiceport disconnect ack FXS only Configures the voice port to return an acknowledgment upon receipt of a disconnect signal The FXS port removes line power if the equipment on the FXS loop start trunk disconnects first This is the default The no disconnect ack command prevents the FXS port from responding to the on hook disconnect with
46. riable length dial peer destination patterns dial plans The seconds argument is the interdigit timeout wait time in seconds A valid entry is an integer from 0 to 120 The default is 10 Step4 Router config voiceport timeouts ringing seconds Specifies the duration that the voice port allows infinity ringing to continue if a call is not answered The keyword and argument are as follows e infinity lIndicates that ringing should continue until the caller goes on hook e seconds Specifies the number of seconds to allow ringing without answer The range is from 5 to 60000 The default is 180 Step5 Router config voiceport timeouts wait release Specifies the duration that a voice port stays in the seconds infinity call failure state while the Cisco device sends a busy tone reorder tone or an out of service tone to the port The keyword and argument are as follows e infinity lIndicates that the voice port should not be released as long as the call failure state remains e seconds Specifies the number of seconds to allow before the call is released The range is from 3 to 3600 The default is 30 Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module Timing Commands Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Configuration Tasks W To change timing parameters use the following commands as appropriate i
47. rt 1 0 0 a EA exe FXS FXS mat 5 Figure 2 FXS and FXO Signaling Interfaces Voice port Serial or Serial or Voice port 1 0 0 Ethernet port Ethernet port 1 0 0 37758 FXS and FXO Interfaces An FXS interface connects the router or access server to end user equipment such as telephones fax machines or modems The FXS interface supplies ring voltage and dial tone to the station and includes an RJ 11 connector for basic telephone equipment keysets and PBXs An FXO interface is used for trunk or tie line connections to a PSTN CO or to a PBX This interface is of value for off premise station applications A standard RJ 11 modular telephone cable connects the FXO voice interface card to the PSTN or PBX through a telephone wall outlet Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module HI Feature Overview FXO and FXS interfaces indicate on hook or off hook status and the seizure of telephone lines by one of two access signaling methods loop start or ground start The type of access signaling is determined by the type of service from the CO standard home telephone lines use loop start but business telephones can order ground start lines instead Loop start is the more common of the access signaling techniques When a handset is picked up the telephone goes off hook this action closes the circuit that draws current from the telephone company CO and indicates a change in st
48. table use the show call history voice command To limit the display to the last calls connected through this router use the keyword last and define the number of calls to be displayed with the argument number To limit the display to a shortened version of the call history table use the brief keyword Router show call history voice last number brief Troubleshooting Tips The following sections will assist in analyzing and troubleshooting voice port problems Troubleshooting Chart page 24 Voice Port Testing Commands page 25 To troubleshoot the high density analog network module perform the following steps To display the ccaal2 function calls during call setup and teardown use the debug ccaal2 session privileged EXEC command To trace the state transition of the RAS state machine based on the processed events use the debug cch323 ras privileged EXEC command To enable debugging for DSP API message events use the debug dspapi all EXEC command To display ASN1 contents of RAS and Q 931 messages use the debug h255 asn1 privileged EXEC command To enable debugging for Host Port Interface HPI message events use the debug hpi all EXEC command To display debugging information for all components of the Voice Call Manager use the debug voice all privileged EXEC command To trace the execution path through the call control API use the debug voip ccapi inout EXEC command To trace error logs in the call control API us
49. tains off hook for the duration of the call loop start Use the loop signaling format On hook and off hook states are represented by the absence or presence of current in the loop Loop start is used for signaling over subscriber line circuit or loop Loop start might have two problems of glare state and no disconnect recognition NM network module PSTN Public Switched Telephone Network RAS Registration Admissions and Status Protocol SAS Signaling Access Server Also called a signaling controller A server based on TransPath system technology that interfaces between the NAS and the SS7 signaling network SVC switched virtual circuit T1 24 64kpbs timeslots on a 1 544 Mbps serial interface VAD Voice Activity Detection silence suppression Bandwidth on the packet network is used only when someone is speaking Wink TelCo terminology for a specific transition of the signaling bits on a T1 line If the originating state of the signaling bits indicates on hook then a wink is an on hook to off hook to on hook transition The timing of the wink and the values of the signaling bits for on hook and off hook can depend on signaling type Wink Start The terminating side responds to an off hook from the originating side with a short wink This wink tells the originating side that the terminating side is ready to receive addressing digits After receiving addressing digits the terminating side then goes off hook for the
50. th PSTN calls because the bandwidth of calls is fixed and each call has a dedicated circuit for the duration of the call However in Voice over IP VoIP networks data traffic might be bursty and jitter from the packet network can become an issue Especially during times of network congestion packets from the same conversation can arrive at different interpacket intervals disrupting the steady even delivery needed for voice calls Cisco voice gateways have built in jitter buffering to compensate for a certain amount of jitter the playout delay command can be used to adjust the jitter buffer Cisco IOS Release 12 2 2 XT and 12 2 8 T Cisco High Density Analog Voice and Fax Network Module amp Feature Overview W Normally the defaults in effect are sufficient for most networks However a small playout delay from the jitter buffer can cause lost packets and choppy audio and a large playout delay can cause unacceptably high overall end to end delay Note Prior to Cisco IOS Release 12 1 5 T playout delay was configured in voice port configuration mode For Cisco IOS Release 12 1 5 T and later releases in most cases playout delay should be configured in dial peer configuration mode on the VoIP dial peer that is on the receiving end of the voice traffic that is to be buffered This dial peer senses network conditions and relays them to the DSPs which adjust the jitter buffer as necessary When multiple applications are confi
51. y the type of equipment connected to the network or by local country specific conditions Incorrect input or output levels can cause echo as can an impedance mismatch Too much input gain can cause clipped or fuzzy voice quality If the output level is too high at the remote router s voice port the local caller hears echo If the local router s voice port input decibel level is too high the remote side hears clipping If the local router s voice port input decibel level is too low or the remote router s output level is too low the remote side voice can be distorted at a very low volume and Dual Tone Multi Frequency DTMF may be missed Echo Cancellation Echo is the sound of your own voice reverberating in the telephone receiver while you are talking When timed properly echo is not a problem in the conversation however if the echo interval exceeds approximately 25 milliseconds it is distracting Echo is controlled by echo cancellers In the traditional telephony network echo is generally caused by an impedance mismatch when the 4 wire network is converted to the 2 wire local loop In voice packet based networks echo cancellers are built into the low bit rate codecs and are operated on each DSP Adaptive Jitter Buffering Delay can cause unnatural starting and stopping of conversations but variable length delays also known as jitter can cause a conversation to break and become unintelligible Jitter is not usually a problem wi
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