Hardware manual

Electra Elite Issue 8
System Hardware Manual 5 - 39
4.6 COIB(8)-U20/U30 ETU
4.6.1 Description
This ETU can function the same as the COI(8)-U( ) or
COID(8)-U( ) ETU to provide Central Office Interface.
Only the COIB(8)-U20/U30 ETU can support the CO
Message Waiting Indication Feature. Transmit and
receive pad controls have been added to the COIB(8)-
U20/U30 ETU (S9500). Ground Start trunks are not
supported. When the ETU is set for COID mode, Loop
Start trunks and Caller ID trunks are supported. Caller ID
does not work in the COI mode.
This ETU contains circuitry for outside ring detection,
holding, dialing, and control functions.
This ETU can provide a CAMA trunk for E911.
CAMA trunk support is provided on COIB(8)-U( ) ports 3
and 7 only.
When functioning as a COI(8)-U( ) or COID(8)-U( ) ETU
only DTMF signaling is supported. Tip and Ring electrical
fuses are provided to comply with UL 1459 requirements.
Refer to Figure 5-22 COIB(8)-U20/U30 ETU.