3-28 C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUALDIRECT INPUT AND OUTPUT COMMUNICATIONS CHAPTER 3: INSTALLATION3AWG 24 twisted shielded pair is recommended for external connections, with the shield grounded only at one end.Connecting the shield to pin X1a or X6a grounds the shield since these pins are connected internally to ground. Thus, ifpin X1a or X6a is used to ground the shield at one end, do not ground the shield at the other end. This interface module isprotected by surge suppression devices.Figure 3-29: G.703 interface configurationThe following figure shows the typical pin interconnection between two G.703 interfaces. For the actual physicalarrangement of these pins, see the Rear Terminal Layout section earlier in this chapter. All pin interconnections are to bemaintained for a connection to a multiplexer.Figure 3-30: Typical pin interconnection between two G.703 interfaces3.4.3.2 G.703 selection switch procedures1. With the power to the relay off, remove the G.703 module (7R or 7S) as follows. Record the original location of themodule to help ensure that the same or replacement module is inserted into the correct slot.2. Simultaneously pull the ejector/inserter clips located at the top and at the bottom of each module in order to releasethe module for removal. (For more information on accessing modules, see the Maintenance chapter.)3. Remove the module cover screw.4. Remove the top cover by sliding it towards the rear and then lift it upwards.5. Set the timing selection switches (channels 1 and 2) to the required timing modes.6. Replace the top cover and the cover screw.7. Re-insert the G.703 module. Take care to ensure that the correct module type is inserted into the correct slot position.The ejector/inserter clips located at the top and bottom of each module must be in the disengaged position as themodule is inserted smoothly into the slot. Once the clips have cleared the raised edge of the chassis, engage the clipssimultaneously. When the clips have locked into position, the module is inserted fully.NOTEPin nomenclature differs from one manufacturer to another. It is not uncommon to see pinouts numbered TxA,TxB, RxA, and RxB. In such cases, assume that “A” is equivalent to “+” and “B” is equivalent to “–.”842773A3.CDR~8a~8b7SRx +Tx +ShieldTx –ShieldRx –Tx –Rx +Tx +Rx –G.703 communications~2b~6a~7a~1b~1a~3a~6b~7b~2a~3bG.703channel 2G.703channel 1SurgeSurgeX8aX8b7SRx +Tx +ShieldTx –ShieldRx –Tx –Rx +Tx +Rx –G.703 communicationsX2bX6aX7aX1bX1aX3aX6bX7bX2aX3bG.703channel 2G.703channel 1SurgeSurge831727A5.CDRX8aX8b7SRx +Tx +ShieldTx –ShieldRx –Tx –Rx +Tx +Rx –G.703 communicationsX2bX6aX7aX1bX1aX3aX6bX7bX2aX3bG.703channel 2G.703channel 1SurgeSurge
