Removing And Replacing Model 3920Plus Modems; Model 3921Plus Modem Installation - Paradyne Comsphere 3920Plus Installation And Operation Manual

COMSPHERE 392xPlus Modems
Removing and Replacing Model 3920 Plus Modems
To remove and replace a Model 3920Plus modem, perform the following steps:
1. Make sure the modem is offline, and press the modem's rear panel power switch to the
2. Disconnect the power cord from the ac power outlet, and then disconnect the dc power
3. Disconnect the leased-line and dial modular cords from the modem's rear panel.
4. Disconnect the DTE interface cables from the modem's rear panel.
5. Install the replacement modem as described in the Model 3920Plus Modem Installation
Model 3921 Plus Modem Installation
The Model 3921Plus is designed for installation in a COMSPHERE 3000 Series Carrier which
supplies both the operating power and the leased and/or dial network connections. For additional
information about the COMSPHERE 3000 Series Carrier, refer to the COMSPHERE 3000 Series
Carrier, Installation Manual.
The COMSPHERE 3000 Series Carrier has 17 slots which can hold up to 8 Model 3921Plus
modems and one shared diagnostic unit (SDU). The SDU is required when the modems in the
carrier are controlled by an NMS, or when multiple carriers in a cabinet configuration are to be
controlled by a single shared diagnostic control panel (SDCP). The SDCP of the COMSPHERE
3000 Series Carrier is the user interface to the Model 3921 modem. A single SDCP can control up
to eight carriers.
The installation of a Model 3921Plus varies slightly if an SDCP is installed on the front of the
carrier. To install a Model 3921Plus modem into the carrier without an SDCP, perform the
following steps:
1. At the rear of the carrier, install the rear connector plates. Make sure the plates use the
2-8
OFF position.
cable from the connector on the rear of the modem.
If the modem is to be removed for service, return it to AT&T Paradyne using the
procedures described in Government Requirements and Equipment Return in Chapter 1.
section of this chapter, and configure it the same way as the modem being replaced.
If the Model 3921 Plus is removed from the carrier, always use a
ground strap when handling the modem. Always store the
Model 3921 Plus in an antistatic bag when it is removed from
the carrier.
same slot positions as that intended for the modem.
Loosely fasten the plates. This allows for slight adjustments later when installing the
modem.
April 1995
CAUTION
3920-A2-GN31-10