2 - 56 Chapter 2Chapter 2 - PCB Installation and Startup2.7.2 Analog Trunk (4COIDB) Daughter Board (Figure 2-28 - Figure 2-35)The 4COIDB is used to provide 4 additional ports for loop/ground start trunks. The PCB is connected to a4COIU PCB to provide a total of 8 ports for the combined PCB (refer to 2.7.1 Analog Trunk (4COIU) PCB(Figure 2-27) on page 2-53).This daughter board can also be installed on the Digital/SLT Combination PCB (082U). This combined PCBwill provide 8 digital extension ports, 2 analog extension ports, and 4 trunk ports.The analog trunk daughter board provides:● 4 analog loop start/ground start trunk circuits● 4 Caller ID Circuits● Connector for COIU or 082U PCBThe 4COIDB consumes 4 trunk ports ranging between ports 001-200. The CN2 connector providesconnection to 4 analog trunk ports, which are polarity sensitive (tip to tip, ring to ring). The power failurecircuits (CN3), however, are not polarity sensitive.! Important !● When using the COIU/COIDB for ground start trunks, the PBX groundmust be connected as described on page 1-55 or the trunks will notfunction correctly.● The trunk ports are polarity sensitive. Be careful when wiring the trunks.● When connecting the RJ61 cables to the COIU/COIDB, note theposition of the Power Failure connector (CN3). Do not confuse thisconnector as the trunk connector (CN2).● Switching from Loop Start to Ground Start is set in systemprogramming.
