NEC Electra Elite 192, Hardware Manual

Page: 217 / 369

Electra Elite Issue 6
System Hardware Manual 5 - 71
5.6 OPX(2)-U10 ETU
5.6.1 Description
The OPX(2)-U10 ETU is the interface for two off-premise
extensions. This ETU has a built-in ringing generator
(RSG). A maximum of 1600
Ω
of loop resistance (including
about 200
Ω
for the Single Line Telephone) is acceptable
between the OPX(2)-U10 ETU and a Single Line
Telephone.
This ETU also provides circuitry for loop status detection,
talk battery, sending ringing signals from the RSG unit to
the Single Line Telephones, and dial pulse detection.
The PBR circuit in the CPUB( )-U10 ETU or the
PBR( )-U10 ETU is required with Single Line Telephone
Connection.
Figure 5-40 OPX(2)-U10 Unit