Com4 (Central Office Module - 4 Circuits) - Comdial DX-80 Installation & Maintenance Manual

channels are used for the digital voice channel requirements. The DPM8 is controlled directly from the
408M/E (therefore there is no heartbeat LED located on the DPM8.)
Each digital station interface is protected against circuit wiring shorts by an over-current protection
Polyswitch. The digital station circuit requires only one cable pair to operate and is not polarity sensitive.
Physical connection of digital port terminals (DET and DSS) to the DPM8 module is made through
convenient RJ-11 connectors along the bottom edge of the module. Depending on the site installation
requirements the installer may choose to route terminal (station) wiring directly into the KSU cabinet and
connect the individual terminal cables to the RJ-11 extension port desired via field crimped RJ-11 plugs.
This streamlined installation capability can eliminate the traditional cross-connect field hence reduce costs of
installation. (Be advised that we do not recommend this practice since it is inherently difficult to
service. When using field-crimping tools, use quality tools. Cheap tools yield cheap results.)

COM4 (Central Office Module - 4 Circuits)

The COM4 module is installed in the dedicated position via J1 of the 408M/E. The COM4 interfaces 4 loop-
start CO (Central Office [Telephone Company]) lines. Since one COM4 may be installed in KSU1 and one
COM4 may be installed in KSU2, the DX-80 system CO line capacity may be expanded to interface 16 total
CO lines.
The COM4 module is shipped with four (4) mounting stand-offs used to install the board into the KSU1 or
KSU2. Five RJ11 jacks are provided along the bottom edge of the COM4 module for connection of one
power failure telephone and the four CO lines.
CO lines are terminated at the site by the Telephone Company (RBOC or equivalent) at a point of interface
called the Demarcation (Demarc). When ordering CO lines for the site, request termination on RJ11 type
jacks. Doing so allows CO line(s) to easily be extended to the COM4 RJ11 connector. (One CO line per jack
and connector.)
P7290 IMM
DX-80 I M
NSTALLATION AND AINTENANCE
Figure 4: DPM8 (Digital Port Module - 8 Port)
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ANUAL