FourthRack G.704 Line Card User Guide
Contents
1. Closed Open Closed 128 Kbps 132 Open Closed Closed 204885 Kbps 0331 Closed Closed Closed Fourthtrack Systems FourthRack G 704 Rev 1 1 2 Ref 502 634 002 Note 1 Gapped clocking is used to accommodate this data rate Clock speed is 2048 Kbps Note 2 Continuous clock Note 3 Clear channel unstructured G 703 operation 4 3 Management capability The FourthRack is available with management The management is supported by using a different power supply module that includes the management function The FourthRack may be used with either one or two of the management enhanced power supplies providing resilience for both power and the management function Configuration parameters selected using LK11 may be overridden via FourthRack management Management selected configuration options are maintained in non volatile memory when the card is removed or when power is lost If set to read only the FourthRack G 704 will power up with the configuration defined by its LK4 settings If set to read write the FourthRack G 703 will power up with the configuration defined by management and saved in its non volatile memory For full details on the management functionality refer to the User Guide supplied with the rack 4 4 Interface selection on dual function X 21 V 35 version The enhanced version of the FourthRack G 704 Line Card can support both X 21 and V 35 DTE The DTE interface function is selected using a2. with the FourthRack G 704 superseding the MicroMux G 704 RM line card The FourthRack Chassis has fourteen line card slots and two power supply slots one at each end of the chassis The FourthRack Chassis can be used with either a single power supply or dual power supplies for resilience Auto ranging self sensing AC power supplies and DC power supplies 48VDC are available Please refer to the FourthRack Chassis documentation for further information 2 Installation On unpacking the FourthRack G 704 Line Card you should find the unit and this manual If there are any questions please refer to your supplier 2 1 Connection to a 75 ohm un balanced G 703 E1 network For use on a 75 ohm un balanced service connection should be made using the two B N C connectors on the front panel of the FourthRack G 704 Line Card These are labelled as Rx and Tx Your G 703 carrier service equipment may be labelled with transmit and receive The FourthRack G 704 LC RX port should be connected to the receive side of the carrier equipment The FourthRack G 704 TX port transmits carrier and this should be connected to the out bound port of the carrier service 2 2 G 703 75 ohm Cable Schedule Connections should be made using 75 ohm co axial cables with B N C connectors The co ax cables required are two off 75 ohm co ax cables of 5mm diameter which must be terminated in male BNC connectors The maximum cable attenuation must be 6db at 1024kHz
3. Enabled DTE RXD Clock Not by R48 default Inverted 13 14 DTE RXD clocked from DTE RXD clocked from DTE by R47 recovered G 703 timing TTC see note 1 on timing default skew below 11 12 AIS disable AIS enable default by R46 9 10 G 703 Data Inverted G 703 Data Not Inverted by R45 default see note 2 below 7 8 by R44 56 See below by R43 4 2 Data Rate Timeslot allocation 3 4 Default is 2048 Kbps clear channel by R42 1 2 G 703 Clock Slave default G 703 Clock Master see by R41 MTTC for source Note 1 used to cancel skew in loop timing due to buffers and cable propagation delays Recovered G 703 clock is presented on DTE CLK to be looped back at the far end on DTE TTC Note 2 the normal or default operation is with the data inverted NB Fitting the link inverts the data from this normal state This is consistent with the DINV ON state displayed by the managed unit user interface and the switch being in the ON position for standalone units 4 2 Data rate timeslot allocation Links 3 4 5 6 and 7 8 are used to set the data rates manually Please refer to the table below Data rate Timeslot allocation 3 4 5 6 7 8 1984 Kbps 1331 Open Open Open 1920 Kbps 1515817531 Closed Open Open 1024 Kbps 1316 Open Closed Open 1024 Kbps 1315817 Closed Closed Open 512 Kbps 138 Open Open Closed 256 Kbps 134
4. Fourthtrack FourthRack G 704 Line Card User Guide Fourthtrack Systems Unit 11 Lowfield Green Caversham Park Reading RG4 6NZ England Telephone 0118 946 3061 Fax 0118 946 3091 Web www fourthtrack co uk Email info fourthtrack co uk Communications answers for the World Market Fourthtrack Systems FourthRack and MicroMux are trademarks of R J Barrett Fourthtrack Systems FourthRack G 704 Rev 1 1 2 Ref 502 634 002 1 Introduction The Fourthtrack Systems FourthRack G 704 Line Card is a derivative of the highly successful MicroMux G 704 The FourthRack G 704 Line Card has been engineered to reduce cost and increase functionality in this expanding sector of the market and thus enhance Fourthtrack s position as the market leading provider of G 703 G 704 Data Service Units DSUs It is designed to enable the connection of data communication systems to carrier services or private services such as microwave links that are presented as G 703 G 704 at 2 048Mbps The standard model supports an X 21 DTE with 75 ohm un balanced G 703 termination The enhanced version can support both X 21 and V 35 DTE with 75 ohm un balanced termination Both versions are also available with 120 ohm balanced termination of the G 703 network connection The FourthRack G 704 Line Card is designed to be used in the FourthRack Chassis The FourthRack chassis is a next generation rack mount system that supersedes the MegaChassis
5. The attenuation characteristics should follow the root f law Cable type RG59 or 2002 or equivalent should meet this specification 2 3 Connection to a 120 ohm balanced G 703 E1 network For use on a 120 ohm balanced service connection should be made using the RJ45 connector on the front panel of the 120 ohm version of the FourthRack G 704 LC This is labelled as RJ45 The pin out for the RJ 45 is as defined for ONP CTR 12 and is given in the specification section 2 4 Status Indicators There are five LED status indicators on the front panel of the FourthRack G 704 Line Card Reading from the top of the front panel these are labelled P N C T and L The green P LED indicates that the FourthRack G 704 LC is receiving power from the FourthRack back plane The FourthRack Chassis and the FourthRack G 704 support hot swap The FourthRack G 704 has a built in power up control system The P LED will illuminate a few seconds after the FourthRack G 704 Line Card is inserted into the rack and the back plane connection has been made The green N LED indicates that the FourthRack G 704 Line Card is receiving correctly encoded data from the line interface equipment The amber C LED indicates that the FourthRack G 704 Line Card is set to clock master mode See set up section for setting the clock master mode The amber T LED will illuminate when the use of the Terminal Timing option is selected See set up se
6. ction for setting the terminal timing mode The amber L LED will illuminate when the loop back condition is selected See below for Loop Back operation 2 5 Loop back Control Loop Back can be selected by pressing the small recessed push button switch between the T and the L indicators labelled LB Loop back mode is cancelled by pressing the LB switch again If the Loop Back mode is not deselected using the switch the Line Card will automatically revert to its normal operating mode after 2 minutes 3 Installation 3 1 Connecting to DTE Connection to the DTE is made using the 15 way D socket Versions of the FourthRack G 704 Line Card are available that support X21 or X21 and V35 The pinout is given in the specification section 3 2 Clock master clock slave settings When using a FourthRack G 704 Line Card system in conjunction with a MicroMux G 703 4 or when using a FourthRack G 704 LC at either end of a 2048kbit s circuit in clear channel operation one of the units should be set to clock master The Fourthtrack Systems recommendation is to set the system that is closest to the network core to clock master and the unit that is closest to the subscriber customer site to clock slave 3 3 Data polarity and clock polarity settings The data transmitted and received on the G 703 side of the FourthRack G 704 could have originated on another piece of equipment It is not uncommon for the data to be inverted by G 703 terminating eq
7. jumper LK17 connects Receive Shield to ground 5 5 DTE Connector Chassis 1 wee 9 TXDB TXDA 2 e 10 mc nc 3 11 RXDB RXDA 4 e 12 INDB NDA 5 L 13 CLKB CLKA 6 1 e 4 TICB TCA 7 e i ne Ground 8 lig 15 way D type Socket 5 6 Environmental The FourthRack G 704 Line Card is designed to operate under the following conditions Ambient temperature Relative humidity Atmospheric pressure Power requirement 5 to 45 degrees Celsius 10 to 90 percent non condensing 86kPa to 106kPa Powered via the FourthRack chassis
8. link field identified as V X It is located toward the front of the Line Card adjacent to the DTE connector Links in the V X link field are three position One or other option must be selected for the DTE interface to function DTE interface status is readable by management however as the links in this field control signal termination and drivers they cannot be overridden by management Ident V 35 X 21 Ident V 35 X 21 LK8 V X LK15 V X LK13 V X LK16 V X LK14 V X 5 Specifications 5 1 On Board Master Clock Operating Frequency 2 048 MHz 50 PPM 25 deg C 5 2 Network Interface Signals Specification The Network Interface conforms to CCITT specification G 703 and ETSI Open Network Provision for digital unstructured leased line D2048U Transmit 2 37 V into 75R 10 3 00 V into 120R 10 Min 8 dB Max 14 dB Output Pulse amplitude Return Loss Receive Sensitivity Below 0dB 2 4 V 10dB Loss of Signal Threshold 0 3V Return Loss 18 dB Allowable consecutive Zeros before LOS 190 bits 5 3 Network Connectors Two versions of the FourthRack G 704 Line Cards are available 75 Ohm Unbalanced 120 Ohm Balanced G 703 RJ45 Pin Function 1 amp 2 Rx pair from network 3 Shield reference point 4 amp 5 Transmit pair to network 5 4 Shield reference point Note that the Receive Shield reference point is taken to ground via a link field Fitting the
9. uipment The FourthRack G 704 has the option to invert or not invert the data transmitted and received on the G 703 port See the set up section for the default setting and changing the data polarity In some cases when using an X 21 interface the data received from the DTE may be mis aligned with the X 21 timing signal and this can cause errors This situation can usually be overcome by changing the polarity of the clock used to clock in the received data with respect to the X 21 timing signal The FourthRack G 704 has the option to change the polarity of the clock used to clock in received data See the set up section for the default setting and changing the clock polarity 4 Set up 4 1 Jumper functions and default settings The start up configuration of the FourthRack G 704 Line Card is controlled by jumpers grouped in link fields The primary link field is identified as LK11 It is located toward the rear of the Line Card adjacent to the back plane connector In a managed system the start up configuration of the FourthRack G 704 Line Card is read from NV RAM or up loaded from the FourthRack Management Card as defined by the management settings Configuration Jumper Table Ident Open Closed 21 22 Read Write Managed use Read Only for Managed amp by R18 only Unmanaged use default 19 20 TSO Disabled default TSO Enabled by R51 17 18 LIU CRC4 by R50 default 15 16 DTE RXD Clock Inverted Disabled LIU CRC4
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