Installation manual

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The Model 3921Plus derives ac power from the COMSPHERE 3000 Series Carrier’s backplane, which is a
common bus to all devices installed in the carrier. The user interface to any Model 3921Plus is through the shared
diagnostic control panel (SDCP), an optional feature which operates in a manner similar to the DCP on the
Model 3920Plus. For a better understanding of DCP operation, refer to Chapter 3, DCP Operation, in Document
No. 3920-A2-GN31.
The COMSPHERE 3000 Series Carrier has a total of 17 slots. The first slot, Slot 0, is reserved for the shared
diagnostic unit (SDU) while the remaining 16 slots can house up to 8 Model 3921Plus modems, or a combination
of Model 3921Plus modems and other units. For more details on the COMSPHERE 3000 Series Carrier, refer to
the COMSPHERE 3000 Series Carrier, Installation Manual, Document No. 3000-A2-GA31.
392x Plus Modem Package
After opening the modem’s package, check for damage and verify that the following items are present:
For the standalone model
• Installation instructions
• Model 3920Plus modem
• Power supply with power cord
• One 6-position, 4-wire modular cord
• One 8-position, 8-wire modular cord
For the carrier-mounted model
• Installation instructions
• Model 3921Plus modem
• Two rear connector plates with two DB-25-S edge card connectors on each plate
If any hardware components are damaged, notify your AT&T Paradyne representative. Return equipment using
the procedures described in the Government Requirements and Equipment Return section.
Customer-Supplied Equipment
The following customer-supplied equipment is required to complete a data communications system using the
Model 3920Plus modem:
• DTEs with available EIA-232-D serial ports.
• Standard EIA-232-D cables with DB-25-P (plug) connectors at one end to attach to the modem.
• One or more of the following modular leased or dial network interfaces:
— JM8 for leased-line applications.
— RJ11C for dial permissive applications.
— One 8-position, 8-wire modular cord (for leased backup purposes).