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6 - 28 Installing ETUs (Circuit Cards)
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Document Revision 3 Electra Elite IPK II
5.3 COI(4)/(8)-U( ) ETU
5.3.1 Description
The COI(4)/(8)-U( ) ETU is the Central Office interface. The COI
ETU contains circuitry for outside ring detection, holding, dialing, and
control functions.
This ETU can provide a CAMA trunk for Enhanced E911.
The COI(8)-U( ) ETU has identical circuits to serve up to eight CO
trunks that can be any combination of Loop Start or Ground Start
with DTMF signaling. The COI(4)-U( ) ETU is for Loop Start trunks
with DTMF signaling only. ETU Tip and Ring electrical fuses are
provided to comply with UL 1459 requirements.
Refer to Figure 6-14 COI(8)-U( ) ETU.
Figure 6-14 COI(8)-U( ) ETU