Applications; Multipoint; Dual-Leased Backup; Msd - Paradyne COMSPHERE 3920Plus Technical Reference Manual

COMSPHERE 392xPlus Modems

Applications

Multipoint

Multipoint is available in all 392xPlus modem models. It utilizes leased-line circuits for time
sharing the same front-end processor (FEP) port with multiple remote locations. The FEP (via the
control modem) regulates traffic on the line by continuously polling the tributary DTE(s) in a
predefined sequence. Only one tributary can communicate with the control modem at a given time.
Modems configured for Trellis Multipoint (TMp) cannot be used in a point-to-point, constant
carrier application. (Refer to the
Mode

Dual-Leased Backup

Dual-Leased Backup is available in all 392xPlus modems. It enables a 2-wire leased line to be
used as the backup facility instead of the normal 2-wire dial line. Plug the leased line into the jack
labeled DIAL on the back panel of the modem (see
and enable the Dual_Leased_Ln configuration option. (Refer to the
Mode
configuration options.) Except for dialing, ring indication, and call progression functions, you
control the backup function as if it were a normal dial backup.

MSD

The Modem Sharing Device (MSD) is only available in 392xPlus multiport modems. It allows
from 2 to 4 physical ports to share a communication channel. When the MUX Mode option is set
to TDM/MSD on a tributary, and at least one port has the MSD mode setting enabled, then MSD is
enabled. For more information, refer to the
Branch, for configuration options or the
configurations in Appendix G, Sample Configurations.
When MSD mode is enabled:
• The MSD Control configuration option is added at the end of the Mux Sub-Group.
• The EIA Port Sub-group includes the RTS Antistream configuration option.
Digital Bridging
The Digital (DTE) Bridging application is only available in 392xPlus multiport modems. It
provides the ability for dial backup of a multipoint configuration by bridging the signal on the
digital side of the FEP-end modems. In this configuration, only two ports (both on the FEP side)
are used on the control and backup modems. Data received on Port 1 is transmitted across the
communication link, as well as looped back out of Port 2. Data received across the communication
link and on Port 2 is sent out of Port 1. For more information, refer to the
of Chapter 5, Configure Branch, for information on the configuration option (DTE Bridge), or
Appendix G, Sample Configurations, for the
1-8
Leased Line — Multiport Mode
section in Chapter 5, Configure Branch, for configuration options.)
or the Leased Line — Singleport Mode
October 1998
or the
Figure 2-2 in Chapter 2, Modem Installation),
section in Chapter 5, Configure Branch, for
Multiport Mode section of Chapter 5, Configure
Point-to-Point MSD and Multipoint MSD
Digital Bridging sample configuration.
Leased Line — Singleport
Leased Line — Multiport
sample
Multiport Mode section
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