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COMSPHERE 3900 Series Modems
1-2 November 1996 3910-A2-GN32-30
• Mixed inbound rates for multipoint applications.
• Convenient migration to new or optional features through software downloading.
•
Extended data circuits with diagnostics.
• Network management system (NMS) support through the COMSPHERE 6800 or
6700 Series NMS using Advanced Diagnostic protocol (ADp).
•
Complement of self-tests, local and remote loopbacks.
• CCITT V
.42bis and MNP Class 5 data compression.
• Virtual error free data integrity with CCITT V.42 and MNP Level 4 error control.
•
Dial access security
.
• Automatic and manual backup with standby capabilities for 4-wire/2-wire leased-line
applications. (The backup facility may be either a 2-wire dial line or a 2-wire leased line.)
Multipoint Applications
In multipoint applications, leased-line circuits are used 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
Leased Line
section in Chapter 4 for configuration options.)
Leased Backup Applications
In
leased backup applications, a 2-wire leased line is used as the backup facility instead of the
normal 2-wire dial line. Plug the leased line into the jack labeled DIAL on the rear panel of the
modem (see Figure 2-1 in Chapter 2), and enable the Dual_Leased_Ln configuration option. (Refer
to the
Leased Line
section in Chapter 4 for configuration options.) Except for dialing, ring
indication, and call progression functions, you control the backup function as if it were a normal
dial backup.
COMSPHERE 391x Series Models
The 391x Series family is available in two models: the Model 3910, a 4-wire/2-wire standalone
modem, and the Model 391
1, a carrier-mounted version of the standalone unit. Both models offer a
variety of modulation schemes and network enhancements while still providing reliable,
high-speed data transmission using the latest in modem technology
.