3-30 C70 Capacitor Bank Protection and Control System GE Multilin3.3 DIRECT INPUT/OUTPUT COMMUNICATIONS 3 HARDWARE33.3.3 G.703 INTERFACEa) DESCRIPTIONThe following figure shows the 64K ITU G.703 co-directional interface configuration.The G.703 module is fixed at 64 kbps. The SETTINGS Ö PRODUCT SETUP ÖØ DIRECT I/O ÖØ DIRECT I/O DATA RATEsetting is not applicable to this module.AWG 24 twisted shielded pair is recommended for external connections, with the shield grounded only at one end. Con-necting the shield to pin X1a or X6a grounds the shield since these pins are internally connected to ground. Thus, if pin X1aor X6a is used, do not ground at the other end. This interface module is protected by surge suppression devices.Figure 3–32: G.703 INTERFACE CONFIGURATIONThe following figure shows the typical pin interconnection between two G.703 interfaces. For the actual physical arrange-ment of these pins, see the Rear terminal assignments section earlier in this chapter. All pin interconnections are to bemaintained for a connection to a multiplexer.Figure 3–33: TYPICAL PIN INTERCONNECTION BETWEEN TWO G.703 INTERFACESPin nomenclature may differ from one manufacturer to another. Therefore, it is not uncommon to see pin-outs numbered TxA, TxB, RxA and RxB. In such cases, it can be assumed that “A” is equivalent to “+” and“B” is equivalent to “–”.b) G.703 SELECTION SWITCH PROCEDURES1. Remove the G.703 module (7R or 7S). The ejector/inserter clips located at the top and at the bottom of each module,must be pulled simultaneously in order to release the module for removal. Before performing this action, controlpower must be removed from the relay. The original location of the module should be recorded to help ensure thatthe same or replacement module is inserted into the correct slot.2. Remove the module cover screw.3. Remove the top cover by sliding it towards the rear and then lift it upwards.4. Set the timing selection switches (channel 1, channel 2) to the desired timing modes.5. Replace the top cover and the cover screw.NOTE842773A2.CDRXXXXXXXXXXXX8a8b7SRx +Tx +ShieldTx –ShieldRx –Tx –Rx +Tx +Rx –Inter-relay communications2b6a7a1b1a3a6b7b2a3bG.703channel 2G.703channel 1SurgeSurge831727A3.CDRXXXXXXXXXXXX8a8b7SRx +Tx +Shld.Tx -Shld.Rx -Tx -Rx +Tx +Rx -COMM.2b6a7a1b1a3a6b7b2a3bG.703CHANNEL 2G.703CHANNEL 1SURGESURGEXXXXXXXXXXXX8a8b7SRx +Tx +Shld.Tx -Shld.Rx -Tx -Rx +Tx +Rx -COMM.2b6a7a1b1a3a6b7b2a3bG.703CHANNEL 2G.703CHANNEL 1SURGESURGENOTE
