Installation manual

7
Carrier-Mounted Model 3921 Plus 4-Wire/2-Wire Modem
The carrier-mounted Model 3921Plus modem (Figure 2) installs into a COMSPHERE 3000 Series Carrier. The
Model 3921Plus modem’s faceplate covers two slots in the carrier. It has 20 LED status indicators for displaying
modem activity and an audio speaker jack for the carrier’s optional speaker.
The Model 3921Plus modem’s rear has four edge card connectors that mount into two connector plates located on
the rear of the carrier. Each connector plate has two DB-25-S connectors providing four EIA-232-D DTE
interfaces.
Figure 2. Model 3921 Plus