Technical Product Manual - DCT1900Installation Instructions, Synchronization Distribution Board (SDB) – REX-BRD0006 or ROANB 101 3818-2 Install-DCT1900/R8/mw© 2000-2005Fig. 18–2 Electrical Schematic Diagram18.2 InstallationThe SDB comes as part of the installation set sync port kit (NTMNB 101 107) and must be installedin the cabinet where the CPU1 is going to reside (refer to Paragraph 4.7 of Chapter 4). For theinstallation of the cables to the CPU1 refer to Chapter 19, CPU1 Cabling. The external sync in andout cables are part of the sync port kit and are required if PWT air interface synchronization isneeded in a multi DCT1900 system environment. They must meet the requirements in Paragraph18.3 (see Figure 18-3).18.3 External Sync CableWhen there are multiple DCT1900 systems with overlapping coverage areas it is necessary tosynchronize the CPUs of the systems together. This is done by connecting an external sync cablefrom one of the sync out ports on the master CPU’s sync board to the sync in port on one of theslave CPU’s sync board.A pre-made external sync cable, TSR 951 284, is available. The specifications for this cable areincluded below. If this cable is not long enough then a cable must be constructed on site. Refer tothe enclosed specifications to construct this cable. If the 6 conductor shielded flat cable is notavailable then a single pair of 120 ohm twisted shielded pair may be used.The signal delay in the external sync cable must be determined. For the cable TSR 951 284 it is0.04μs. A cable made on site must be measured using a TDR (Refer to Paragraph 18.4).Once the delay is known, this value is entered into the slave system’s CPU during its’ initialization.Refer to the Cordless System Software User’s Guide (LZB 119 2664), Appendix I, on how to enterthis delay.1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 61 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4X5 X6 X7 X8X1 X2 X3 X4CIRCUIT GNDCIRCUIT GNDGND(shield) GND(shield) GND(shield) GND(shield)SYNC OUT SYNC OUT SYNC OUT SYNC INABABABA'B'To CPU ---------------------------------------------------------To otherCPURJ Connectors
