VT21 manual - PA Comms.com
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1. e g to play message 02 send PO2 is Zone data for messages selected by telephone is returned to the serial port as Z1 Z2 or Z3 for interpretation by the P A Controller gt An upper case H will interrupt any message currently running a G can be sent within 20 seconds to restart the original message k The equipment is powered from 250V A C with an internal carry over battery and charger User Manual VT21 Issue reprint a VT21 odt page 3 of 31 1 2 SYSTEM OVERVIEW The VT 21 is housed in a 19 inch subrack constructed using modular Eurocard 3U height plug in units From left to right they are LA LB LC LD LE LF LG Assembly Identification LA LB LC LD LE LF LG LH LJ Power lock switch and carry over battery Power supply which supplies plus five plus twelve and negative five volts The delay voice store for message 21 Control unit and Display Telephone line interface E amp M type Audio and control module The main voice store for messages 1 20 S533201 S533005 P11001 P11415 P11309 P11151 P12001 Carry over battery unit PSU 3U Voice store Controller Display Telephone Line Interface 3U Recording module 3U Voice store blanking panel blanking panel User Manual VT21 Issue reprint a VT21 odt 12hp 12hp 4hp 12hp 6hp 14hp 8hp 6hp 10hp page 4 of 31 1 3 Features of the Modular Announcer Type VT 21 Equipment practice Equi2. 30 seconds duration Replacement for missing drawing of J subrack Controller Vt Voice Record Prompts ggm Module The first twenty messages are prepared using a microphone at the equipment subrack the controller has a display to show which channel number has been chosen Selection of the message to be replayed is remote controlled from either a DTMF telephone or from serial RS232 commands to a db25 connector on the rear of the VT 21 Message number 21 is the DELAY MODULE up to 32 seconds of message can be recorded over the telephone into a separate VT card The caller is guided by voice prompt recording their own voice for the message text The telephone line interface for the ISDX is a four wire E and M type signalling busy to the PABX when required Serial Port If the telephone is used to select a message the voice prompt requests that the caller makes a Zone selection Zone data for the selected broadcast appears as serial data on the RS232 port Z1 Z2 or Z3 for interpretation by the amplifier control rack The RS232 port is bidirectional messages can be selected by sending P ascii 50 followed by two numbers in ascii format 30 39 The end of a message being played is signalled by E ascii 45 being transmitted from this port An incoming H ASCII 48 will interrupt any message currently running that had been selected using the DTMF if a Go commana is received by the VT
3. LEVEL ACCESS comes from electromechanical days when each digit dialled involved using equipment on various levels When connecting equipment rather than telephones a different approach is made The word Equipment might mean a portion of the telephone switching system another rack of switching or a tie line to a more remote location where a smaller satellite of the main exchange exists The ACCESS should be fast access or near immediate access in contrast with the delay encountered when a ring trip device is accessed and subsequently answers E and M This can be considered to be a version of level access Two signalling wires are used one E the other M they are connected in addition to the speech circuits The speech circuits are free of any D C and only carry audio The two signalling wires are for requesting connection and acknowledging that a connection has been successful To connect two pieces of E amp M equipment together wire the E terminal of one to the M of the other and vice versa These signals are true when grounded with respect to the exchange battery When an E and M interface is used as a remote control port pulling the E wire of the interface to exchange ground or near ground via a resistor will initiate the voice prompt menu The E wire is generally current limited User Manual VT21 Issue reprint a VT21 odt page 9 of 31 5 1 CONTROLS The controls are located on the front pane
4. or Z2 or Z3 via Serial link Wait for up to 20 seconds for a G Go replacement for missing diagram User Manual VT21 Issue reprint a VT21 odt page 29 of 31 APPENDIX D1 Works Order 2017 Testing using the Status board The new plug in unit to the far right provides an extra four character display the purpose of which is to offer more information about the VT21 s operation It decodes some of the diagnostic information that appears from time to time as a single character in the controller four character display Message preparation is one aspect of the enhancement the ability to initiate a message without having the serial control input connected is the other aspect Press button to generate g A message either a pre stored message New Status using local microphone numbers 1 through 20 board or one that has been recorded by the telephone message number 21 will be standing by for a period of a few seconds but shall not be replayed to the audio output unless an upper case G is sent to the VT21 serial input The New Status Board will indicate when the G character is required and can simulate this character arriving at the serial port if the green button is pressed The status board will interpret the w in the controller display and will begin to scroll a message Waiting to Go If the green button is pressed during the waiting time the status board will briefly display Butt and at that point will sim
5. 21 within 10 seconds of the Halt the original message can be restarted the Z data will also be re sent After the 10 seconds is up the VT 21 times out and the DTMF selection is abandoned A dialog exists between the VT 21 and the external controller from time to time T 54 is sent the VT21 responds by sending back a different character D4 is T with high bit set This is intended to satisfy the system s alarms by showing that the VMS is alive and connected User Manual VT21 Issue reprint a VT21 odt page 21 of 31 1 INTRODUCTION continued CONTROL EPROMS There are a total of three control software EPROM fitted inside the VT21 this upgrade only affects the Controller Replacement drawing location of controller Finmware CCNU The firmware is contained in a 2764 type EPROM nearest to the front panel of the controller The revision level of the software can be seen in the led display when the equipment is first powered Existing version is level 2 CCNU2 replacement drawing location of eprom Purpose of upgrade The requirement is as follows Quick Access Default Zone User dials Access code to route from PABX to the VMS the VMS immediately returns a bleep and records the users message once the user hangs up the message is replayed after a few seconds over the default zone zone two Prompt Access User dials access code receives confirmation bleep but because no action has been taken wit
6. 3 1 POWER SUPPLY The PARVA range of modular announcers employ standard Eurocard size plug in units the power source can be specified at time of ordering and can be one of two basic types for A C or for D C operation This announcer has been configured to accept an A C power source and has an internal carry over battery to maintain input power during generator change over The illuminated switch at the rear disconnects the incoming A C The lock switch on the front panel interupts both of the power sources for maintenance purposes The VT 21 requires an input power source of nominally 240 volts A C which is fed to the power supply unit transformed down and rectified to provide the raw D C of 40 55 Volts to the secondary switcher The term secondary switcher refers to a switch mode power supply which does not operate on the mains input but rather that it uses a lower rectified voltage from the transformer secondary which is subsequently chopped by the switching transistor The D C input is stored by an electrolytic capacitor and is chopped by a VMOS power FET at a frequency of about 26KHz The output energy is controlled by varying the on time of the VMOS power FET Pulse Width Modulation and regulated by comparing it s output with a reference The plus five volt rail is the main regulated output the plus twelve is obtained by taking a step up tap from the output choke The auxiliary supply of negative five volts i
7. PA Communications Ltd Trinity Farm 28A Dunton Road Stewkley LEIGHTON BUZZARD LU7 OHZ U K Tel 01525 240945 P A COMMUNICATIONS ANNOUNCER SYSTEM Model VT21 USER MANUAL This document comprises reprints of the original produced by paste and copy from exhumed files the first of which is a file named VT21MAN DOC it was originally prepared for Works Order WO1292 for CCE Calflex VT21MAN DOC Manual dated MARCH 1992 Issue two pages 1 through 18 are numbered as the original Appendix B1 Requirement for Addition of Quick Mode page 19 note the outcome of the requirement differed slightly from this description The third portion starts at page 20 Installation and commissioning instructions for the upgrade software EPROM supplied under P A Communications Works Order 1556 for AGIP UK Ltd pages 20 through 29 are equivalent to 1 through 9 of the original document The final portion relates to the additional Status Board as per works order WO2017 14 March 2013 APPENDIX D1 Testing using the Status board Page 30 APPENDIX D2 Bench testing Page 31 User Manual VT21 Issue reprint a VT21 odt page 1 of 31 The first portion of this document is a reprint of the original produced by paste and copy from a text file called VT2IMAN DOC Manual dated MARCH 1992 Issue two CONTENTS section SYSTEM OVERVIEW 1 VOICE STORES POWER SUPPLY INSTALLATION and COMMISSIONING CONTROLS OPERATING INSTRUCTIONS ona A WwW N User Ma
8. VMS the VMS immediately returns a bleep and records the users message once the user hangs up the message is replayed after a few seconds over the default zone zone two Prompt Access User dials access code receives confirmation bleep but because no action has been taken within the 4 seconds the voice prompts operate as they do at present note the outcome of the requirement was subsequently changed and differs slightly from the description above User Manual VT21 Issue reprint a VT21 odt page 19 of 31 P A COMMUNICATIONS ANNOUNCER SYSTEM Model VT21 UPGRADE SOFTWARE for the V M S INSTALLATION AND COMMISSIONING INSTRUCTIONS This document gives the initial installation and commissioning instructions for the upgrade software EPROM supplied under P A Communications Works Order 1556 for AGIP UK Ltd These instructions are for technical staff trained in handling electrical and electronic apparatus INDEX page 1 Introduction 2 2 Operational Changes Background 4 3 Installation 5 4 Using Quick Mode 6 Appendix A Existing Control Software Appendix B Flow Chart for Telephone Access CCNU2 Software Appendix C Flow Chart for Telephone Access CCNU3 Software Issue A 3 February 1995 User Manual VT21 Issue reprint a VT21 odt page 20 of 31 1 INTRODUCTION The VT 21 VOICE MESSAGE STORE and DELAY MODULE has one common audio output channel for feeding into the P A system It has a capacity of 21 messages each of up to
9. alling is employed sending DTMF MF4 tones to the VT 21 The caller is welcomed by a voice saying THIS IS THE VOICE MESSAGE STORE followed by a short pause after which the caller will be invited to make a selection PLEASE SELECT MESSAGE NUMBER the caller should then dial two digits to select the message PLEASE SELECT ZONE the caller should then dial one digit to select the zone If message number 21 for the delay is selected a further prompt will say PLEASE RECORD YOUR MESSAGE AFTER THE TONE The user can then record their own voice for the message text 21 which is picked up via the telephone handset The message text will automatically be shortened by 0 5 second to mute the handset returning onto the telephone cradle If a message number is selected that is between 1 20 but has nothing recorded the voice will say SORRY THERE IS NO MESSAGE A successful selection will be concluded by the voice saying THANK YOU GOODBYE User Manual VT21 Issue reprint a VT21 odt page 14 of 31 6 1 OPERATING INSTRUCTIONS PREPARATION OF MESSAGES 1 20 If not already done turn on the power to the system by means of the rocker switch on the rear panel The four power leds will illuminate the remaining front panel leds will all light up briefly then extinguish this is a test sequence Plug the monitor earphone into the jack socket Turn the rotary switch to position three Plug the microphone into the DIN so
10. cket the red lamp behind the Record button will illuminate indicating that the Record facility is now available if required a Select Record Mode by pressing the RED BUTTON b Choose the message number the display will show the letter R followed by two digits corresponding to the choice of message number If this is the first time that a message is to be recorded the display will be flashing 00 On pressing the red button again R01 will appear replacing the flashing zeros If recording has already taken place the two digits will correspond to the message that was last recorded The number may either be advanced by repeatedly pressing the red button or automatic advance will take place when the button is held c After a short time the desired message number is is transferred into memory The letter S appears in the display to show selected d Pressing the PTT Push To Talk button on the side of the microphone causes the VT 21 to record e Pressing the GREEN BUTTON on the front of the recording module ends the recording and starts a replay of what has been recorded f A message can be checked using the headphone by making a selection as steps a thru c and then pressing the GREEN BUTTON User Manual VT21 Issue reprint a VT21 odt page 15 of31 6 2 The display on the front of the VT 21 is used to provide information to the user When there is nothing recorded in a message th
11. e access Record spoken message if present or behave as existing Problem with Literal Implementation Should a caller be using a telephone in a noisy location the background noise may trigger the Quick Access mode Solution Use dtmf input to select the Quick Access mode Any button pressed while the Voice prompt is welcoming the caller will cause the messages to truncate select message 21 on zone 2 Benefits of CCNUS All the features of CCNU2 Faster initial access Option to select Quick Access mode No percieved operational changes for existing users Reliable selection even if caller is using a telephone in a noisy location Benefits of CCNU4 All the features of CCNUS3 Shorter delay before telephone message is played over Public Address User Manual VT21 Issue reprint a VT21 odt page 23 of 31 3 INSTALLATION Unscrew and remove the controller plug in board it is the plug in unit with the LED display The control software that is to be changed is contained in a 2764 type EPROM nearest to the front panel of the controller replacement diagram of controller plug in board Remove the existing CCNU2 chip and replace with CCNU3 This will provide Quick Mode If tests show that all is satisfactory remove the new CCNU3 chip and replace with CCNU4 this should speed up delivery of message 21 following replacement of the telephone handset Identification of Software The revision level of the software is the
12. e display will show a n after the message number e g SO8n When a recording is being made and the PTT is not pressed the display will show a p after the message number to signify Pause After a replay message command has been input to the VT 21 the display will show P followed by two digits for the message number and a single digit for the zone number if the request was made via the telephone access A w shows that the VT 21 is waiting waiting for a GO command If nothing is stored in messages 1 20 the display will show NO TEXT and STBY When entering recording mode the display will show Recd User Manual VT21 Issue reprint a VT21 odt page 16 of 31 Appendix A1 COMMAND SECOND COMMAND VT 21 ACTION Messages 1 20 none play the requested message selected by serial send E via serial at end of Pxx message Messages 1 20 none send zone data selected by DIMF wait 20Sec for G play the requested message send E via serial at end of message Message 21 none record into delay module selected by DTMF message send zone data at end of recording send E via serial at end of message Message 21 none play delay message selected by serial P21 send E via serial at end of message Messages 1 20 A stop message immediately selected by serial sent via serial send E via serial Messages 1 20 selected by DTMF A sent via serial stop message immediately send E via
13. ect PD6 U70 UART is mutually exclusive with recording uses port PA2 NEW COMMAND A A Abort aborts current replay E is sent immediately The new A command is present in the existing CCNU2 ASM See SERA in the IRQ By 15 5 92 system has gone to Yarmouth all software works O K User Manual VT21 Issue reprint a VT21 odt page 27 of 31 APPENDIX B2 FLOW CHART for Telephone access CCNU2 This is the voice message store Please select message number Wait for up to ten seconds for user input Evaluation of two tones received store good result in variable TANO Please select zone Wait for up to eight seconds for user input store good result in variable ZNO Thank you Goodbye Transmit Zone Data as Z1 or Z2 or Z3 via Serial link Wait for up to 20 seconds for a G Go replacement for missing diagram User Manual VT21 Issue reprint a VT21 odt page 28 of 31 APPENDIX C2 FLOW CHART for Telephone access CCNU3 CCNU3 O No Delay Telephone line de bounce Please select message number Wait for up to ten seconds for user input A esssescessesssessesssesep r scissessssssersssossssei 2 Tone Set TANO 21 Evaluation of two tones received store good result in variable TANO Please select zone Wait for up to eight seconds for user input store good result in variable ZNO Thank you Set ZNO 2 Gate Chan 21 record Transmit Zone Data as Z1
14. evaluated and the result is re stored again into TANO ZNO 57 Zone number from phone GETZONE invites the caller to Please select zone a tone is collected and stored into ZNO at CKZIN The zone number is eventually sent by serial using subroutine ZTOGO PLAYNO 58 play number User Manual VT21 Issue reprint a VT21 odt page 25 of 31 4 Using Quick Mode This is the voice message store sbeesenacessesscesssnacesscsscesesssecsesa a ss sseseseeesseseeessesesesssasensesssantesscnseessesesesscasesssssnecsessenneeey Dial any Number Set TANO 21 Set ZNO 2 Please record your message After the tone Resssccereseenccesscsnecsssseretssnsensesececsesseenecs sab ecesennceseecesseseecsesscensscenecsesceassssnceresscesscsesssnesscsscesesenel Please select message number Normal Channel 21 selection record User Manual VT21 Issue reprint a VT21 odt page 26 of 31 EXISTING CONTROL SOFTWARE CCNUx ASM continued PRIORITY Text Preparation messages need to be stored for kit to be of use but Message 21 can be used even if NO TEXT is displayed Serial Commands Telephone Input CONTROLLER and CCNUx ASM The controller uses two 28 pin text EPROM PB4 PB5 and PB6 are used to select voice prompt text Ports in use DTMF present SWA 3 PTT PA1 announcer PC1 LEDA 16 I F aN a eee PAS Pe 5 LEDC _ PAS 8 PC6A13 O PPA7 6 PCAN PBO DTMF i pb0 PDO voice prompt PB6 text sel
15. has two leds to show it s status GREEN Play led RED Record led Power Supply has a red led indicating POWER ON and three green leds to show the presence of the three output voltages User Manual VT21 Issue reprint a VT21 odt page 10 of 31 5 2 EQUIPMENT OPERATION Serial Command Channel A DB25 connector is provided on the rear of the equipment sub rack intended for bi directional communication to the P A Controller Commands input to VT 21 P 50 Play Messages may be selected by sending an upper case P ascii 50 followed by two digits in ascii format 30 39 e g P17 Will cause message 17 to be played 48 Halt Causes the VOICE MESSAGE STORE and DELAY MODULE to halt any current message being played at the time Causes a busy condition to be presented to the ISDX provided that no caller has already accessed the system using the telephone 47 Go Informs the MESSAGE STORE and DELAY MODULE that the P A system is not in use and that any message selected by telephone can be replayed Is also used to restart a message that has been halted 41 Abort Causes the VOICE MESSAGE STORE and DELAY MODULE to halt and abandon any current message being played at the time E is returned to indicate end of message 54 Test Performs VMS test character s are returned to indicate the status of the VT 21 51 Query To query if a message has valid tex
16. hin the 4 seconds the voice prompts operate as they do at present Solution 1 Speed up existing operation by eliminating one scrolling message in the led display Phone call replacing it with an instant message Call 2 Provide an additional quick access mode User Manual VT21 Issue reprint a VT21 odt page 22 of 31 2 OPERATIONAL CHANGES Analysis Investigating the test setup at Milton Keynes equipment using the CCNU2 software reacts as follows The VT21 answers a telephone call display scrolls Phone Call in the led display after which the voice prompt says This is the voice message store After a short pause it says Please enter message number There is a delay whilest it scrolls the message during which it isn t possible to interrupt the system The four seconds referred to in the requirement may well be the delay in gaining access while it scrolls Phone Call Also see Appendix B Requirement Quick Access Default Zone User dials Access code to route from PABX to the VMS the VMS immediately returns a bleep and records the users message once the user hangs up the message is replayed after a few seconds over the default zone zone two Prompt Access User dials access code receives confirmation bleep but because no action has been taken within the 4 seconds the voice prompts operate as they do at present This requirement implies that there are two actions the equipment should take following telephon
17. ied Serial input output port is via the DB25f 25 way connector on the rear panel Pin 2 is command input pin 3 is the response output from the announcer controller and pin 7 is ground Krone strip connections Telephone connection Pair 1 brown Audio Pair 10 yellow Voice Response 11 Pair 2 green Audio Pair 27 blue Input 28 purple M wire 13 grey E wire 12 white Busy out 29 red batt 14 black batt 15 Audio Output is via the bottom pair of the Krone connector marked pair 0 coloured brown and pink pair 1 pair we Public audio audio Address User Manual VT21 Issue reprint a VT21 odt page 8 of 31 4 2 TELEPHONE INTERFACE A telephone line as terminated at a customer jack socket NTP is an example of a PSTN two wire connection It carries speech in two directions and has a D C potential across the two wires which is sometimes used to power modern telephones a third component is the 75V 25Hz ringing current which is also sent via the same two wires to alert the customer that a call is waiting The two wire connection is compatible with both the copper wiring that exists between buildings and the telephone exchange building or switch and the simple telephone as described in BS6317 The interface used for a two wire connection to the PSTN or to a PABX is called a RING TRIP interface This interface simulates the simple telephone LEVEL ACCESS The term
18. l of the Record Module plug in unit LF which also contains the audio input preamplification stage VOGAD and a distribution amplifier to provide a signal to each voice store in order that it may be recorded The DIN socket on the front of the record module has two audio input pins pin one is suitable for the microphone and pin three is suitable for tape recorder or Line level There are two press buttons and a rotary switch on the front panel The rotary switch is employed to select which audio signal is fed to the monitor jack socket 1 Delay Voice Store output message 21 2 Voice Prompt 3 Main Voice Store output messages 1 20 Positions 1 and 2 are for test purposes Both press buttons have more than one function The red press button on the record module issues the request for recording command The red press button will light when interlock is satisfied if either microphone or accessory lead is plugged into the DIN socket at the front of plug in unit LF The interlock prevents accidental erasure or unauthorised changes to previously stored messages Messages 1 20 can be prepared by first selecting the message number using the red button The green press button is used to stop recording or to start replay of a selected message INDICATORS Record Module has a lamp inside the Red Record button to indicate that recording mode has been selected see above Voice Stores each voice store
19. nual VT21 Issue reprint a VT21 odt page 2 of 31 1 1 EQUIPMENT OVERVIEW The VT 21 is a Recorded Voice Announcer RVA with two voice stores a VOICE MESSAGE STORE and DELAY MODULE it is constructed modular fashion in a 3U high 19 inch rack The VT 21 has the following facilities t Single audio output channel for feeding into a public address system x Message selection is remote controlled a Commands can be accepted from two sources a tone dialling telephone via a dedicated extension or via a serial port from an external controller There are 21 different messages of up to 30 seconds duration that may be replayed to the P A z Messages 1 20 are recorded by the operator using a microphone connected to the central recording module the controls for message preparation are on the front panel of the rack The audio signal message text is then retained in the main VOICE STORE 2 The entire process of storage and replay of the text involves NO MOVING PARTS is Message 21 is the DELAY MODULE up to 32 seconds of message can be recorded over the telephone The caller is welcomed and guided by an internal voice which invites the user to select zone and then to record their message after the tone The message text as picked up via the telephone handset which is subsequently replayed under external control The serial port is bidirectional RS232 using a DB25 connector Messages may be selected by sending serial ascii
20. numeric portion e g existing version is CCNU2 level 2 it can be seen in the led display when the equipment is first powered Source code file EPROM Checksum CCNU2 ASM 168354 CCNU3 ASM 166EE3 CCNU4 ASM 166D6E Please contact P A Communications technical support for further assistance if required Milton Keynes 6 988 567248 note PA has moved the telephone number at Stewkley is 01525 240945 e mail support pacomms com Thank you for selecting a PA Communications product User Manual VT21 Issue reprint a VT21 odt page 24 of 31 APPENDIX A3 EXISTING CONTROL SOFTWARE STRUCTURE of CCNUx ASM E000 START E200 Control Section E500 VOICE PROMPT E900 FRONT PANEL CONTROLS F000 SUBROUTINES F400 Play Section F600 TABLES F800 INTERUPT ROUTINE IRQ FB00 TEXT POINTERS SETUP Voice prompt FB80 VTABLE for voice prompt FFFA VECTORS IMPORTANT CCNUx VARIABLES RAD 53 Record number This number determines which message is recorded valid range 0 20 It is changed by pressing the record button on the front panel of the record module The value of RAD is sent to the MAV announcer to select the message for recording The value of RAD is also used for playback it is transferred into PLAYNO for review TANO 56 Telephone access number When telephone access occurs GETNUM invites the caller to Please select Message number two tone digits are detected TANO 1st digit DTMF 2nd digit Then the two are
21. play Waiting to Go Press the green button and the status board will display Butt at this point it will simulate an upper case G being sent via the serial link at 9600 baud The VT21 controller will display P21 while it replays User Manual VT21 Issue reprint a VT21 odt page 31 of 31
22. played which may be subsequently restarted within the next 20 seconds Pxx if issued while a message is already playing will cause the running message to stop and be replaced with the new selection will halt the current message and start message number xx instead A Aborts and abandons a selection Should the user have selected message 21 and still be connected when a H occurs they will still be able to store the message Once the user has cleared from having recorded no 21 the telephone interface will then signal busy User Manual VT21 Issue reprint a VT21 odt page 12 of 31 5 4 Status and Data sent from VT 21 E 45 End end of message is signalled when a message has finished Z 5A Zone Zone data the Z is followed by one digit to indicate which zone the user has requested via the telephone e g Z1 Z2 or Z3 Ack 06 Acknowledgement of command input Nak 15 Not Acknowledgement of command input D4 T with high bit set This is the response to the test command T In response to a request for validity of message e g Q17 Y 59 yes Indicates that a message exists N 4E no Indicates that no text has been recorded B 42 busy Indicates that the voice store is busy and cannot presently service that enquiry User Manual VT21 Issue reprint a VT21 odt page 13 of 31 5 5 Using DTMF Telephone The VT 21 can be instructed to replay a selected message to a desired zone A telephone capable of tone di
23. pment operation Length of announcements Delay channel V M S Coding of signals Frequency range Signal to noise ratio Distortion Temperature range Outputs Level Inputs Sensitivities Power requirements Mains Frequency Power Consumption User Manual VT21 Issue reprint a VT21 odt Standard Eurocards Mounted in 3U 19 cardframe By means of front panel controls serial command channel and voice response telephone access maximum text capacity of 32 seconds Twenty messages each of 30 seconds text capacity Standard A law companding code following CCITT Vol lll 2 Rec G 711 712 733 64Kbit s 300 3400Hz 3db 50db less than 4 Operation ODegC 50DegC Storage 20DegC 80DegC balanced output isolated by line transformer Impedance can be set for Low Z or 600 Ohm nominal Odb to public address line input Via front panel DIN socket 7 pin Microphone 200 600 Ohm 210uv Line Tape 47K Ohm 250mv Automatic Recording Level 110 250 V A C or 10 47 63 Hz 30 Watts BT Approval No S 2944 23 G 452230 page 5 of 31 2 1 VOICE STORES The VT 21 has 2 independent voice stores the delay voice store has 32 seconds variable text capacity the main voice store has twenty messages each having 30 seconds capacity The voice store cards used in the equipment are 3U plug in units They each have a control microprocessor which is used to manage the storage and recovery of digital sample
24. s The samples are stored in text memory at a rate of 8000 per second The signal to be recorded is sampled and quantised according to CCITT A Law which is specifically designed for processing communication quality speech The sample so processed becomes an encoded number which is stored into memory It can be seen that the memory needs to be of sufficient size to accommodate the length of text that comprises the message The rate at which memory is used is 64 000 bits per second 64Kbps hence the delay store will require eight memory chips for a message of around 32 seconds The microprocessor is used to store away the samples into the memory it is also used to recover the samples so that the waveform may be reconstructed when the message is to be replayed Hence a similar process to a tape recorder is taking place but doing so with no moving parts no tape nor wear to rotating parts or to any magnetic media Each announcer card has it s own operating software in the form of a plug in read only memory which is non volatile i e it remains if power is disconnected The memory chips that are employed to store the message text are the volatile type known as Dynamic RAM which requires that the VT 21 is kept powered to store the text When the VT 21 is disconnected from the power source by switching off the lock switch it will erase the messages that has been previously recorded User Manual VT21 Issue reprint a VT21 odt page 6 of 31
25. s generated from a separate winding on the ferrite ring upon which the output choke is wound Isolation from earth is provided by the mains transformer allowing the zero volt terminal of the power supply to be internally connected to both mains earth and chassis FUSES locations and values On rear of VT 21 Mains inside IEC receptacle 20mm type 3 15 A M On the plug in unit LA unscrew front panel screws and withdraw F1 Battery mounted on pcb LA 20mm type 3 15 AF On the plug in unit LB unscrew front panel screws and withdraw FS1 Raw D C mounted on PSU pcb 20mm type 5A F FS2 Neg 5V mounted on PSU pcb 20mm type 1AT User Manual VT21 Issue reprint a VT21 odt page 7 of 31 4 1 INSTALLATION and COMMISSIONING The microphone and earpiece for text preparation plug into the front of the recording module the other connections are made at the rear of the VT 21 Microphone Line connection 7 pin DIN socket fitted 1 Mic Hot connection to front panel of Ground Recording module LF Line tape connection KR WwW Record run connect to ground Record pause open connection 5 Record enable connect to ground to make Record button on front panel operational Headphone connection Jack socket on front panel 1 4 2 pole mono socket Headphones impedance 8 600 Ohms A C Mains Power 250 Volts should be connected via the plug in IEC receptacle on the rear panel using the plug in lead suppl
26. serial Messages 1 20 selected by serial Messages 1 20 selected by serial play message xx interrupt first message Pxx Pyy play message yy send E via serial at end of message User Manual VT21 Issue reprint a VT21 odt page 17 of 31 Appendix A2 COMMAND SECOND COMMAND VT 21 ACTION Messages 1 20 selected by serial H sent via serial stop message immediately wait for G to start again at beginning Messages 1 20 selected by DTMF H sent via serial stop message immediately wait for G to start again at beginning M 1 20 serially selected halted by H waiting fora G G sent via serial play all of the message send E via serial at end of message Messages 1 20 selected by DTMF halted by H waiting for a G G sent via serial play all of the message send E via serial at end of message M 1 20 serially selected halted by H waiting for a G nothing sent via serial within 20 seconds timer timeout send E via serial to signify Messages 1 20 selected by DTMF halted by H waiting for a G nothing sent via serial within 20 seconds timer timeout send E via serial to signify User Manual VT21 Issue reprint a VT21 odt page 18 of31 Appendix B1 Requirement for Addition of Quick Mode Quick Access Default Zone User dials Access code to route from PABX to the
27. t Upper case Q is sent followed by two digits in ascii format Y is returned for yes N for no B for busy e g Q17 To enquire about message seventeen User Manual VT21 Issue reprint a VT21 odt page 11 of 31 5 3 Command Priorities 1 Message preparation is the highest command priority this mode can only be entered having first satisfied the interlock by plugging the microphone into the equipment front panel Should the VT 21 be placed in this mode and left unattended it will revert to normal standby after a period of 10 15 seconds In standby the VT 21 is ready to react to either serial commands or to telephone access 2 Serial commands consisting of single ASCII characters from the external public address control system 3 Telephone access the use of DTMF tones in conjunction with the VT 21 s voice prompt The VT 21 interprets the serial commands as having higher priority than the commands input via the telephone access DTMF If during the replay of a telephone selected message an H is sent to the VMS it will hold the selected message The message may be restarted by sending a G within twenty seconds of the H If the P A system remains busy for 20 seconds no G is sent hence the selection is abandoned If multiple interruptions occur the third H will be treated as an Abort the VMS will then send an E to signify this Summary of interrupting command letters H halts the current message being
28. ulate an upper case G being sent via the serial link at 9600 baud User Manual VT21 Issue reprint a VT21 odt page 30 of31 APPENDIX D2 Bench testing A temporary test fixture using a small piece of plexiglass was constructed in order to fully test out the interface to the telephone exchange To the right is a picture of how it connects An external DC of around 12 to 20V is required a bench PSU at 12V was used OTM a The voice prompt audio is heard using a hi z loudspeaker 50 ohm D a toggle switch is employed to simulate the telephone being off _ hook A To test carry out the following y steps With DC applied you operate the toggle switch to simulate the phone being off hook The red LED will light after a short delay The VT21 controller will display Call and the voice prompt will speak This is the voice message store Please select message number At which point a DTMF source is used to enter digits If 01 is entered it will say Sorry There is No Message if 21 is entered it will say Please select Zone select a single digit e g 3 for Zone 3 The VT21 controller will display M213 It will then say Please record your message after the tone one can then begin recording a message on store 21 Toggle the toggle switch to end the call simulates going back on hook The status board will interpret the w in the controller display and will then dis
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