Black Box May-95 Cable Box User Manual


 
8
MULTI-FUNCTION LD CARD
2. Introduction
2.1 Overview
The Multi-Function LD Card is a short-range modem on a dual rack card (it
has a main [front] module and an interface [rear] module). The Card
operates across two wires (half-duplex) or four wires (full- or half-duplex),
communicating synchronously or asynchronously, up to a maximum range of
20 miles (32.2 km). You can set the Card to any of twelve data rates from 1.2
to 57.6 kbps. Local and remote modems on Multi-Function LD Cards always
communicate with each other synchronously. When connected to an
asynchronous RS-232 device, the Card performs synchronousasynchronous
conversion.
The Card has several features that enhance its overall performance,
including automatic equalization, automatic gain control, an antistreaming
timer, transformer isolation, and Silicon Avalanche Diode surge protection.
The Card also has strong diagnostics: It features V.52-compliant bit-error-rate
(BERT) pattern tests and two V.54 test modes. With the Card’s 11 easy-to-read
front-panel LEDs, you can easily monitor the status of data transmission and
diagnostic testing.
The Multi-Function LD Card is fabricated using the latest surface-mount
technology, so you get high-quality short-range-modem performance on a
convenient rack card. The Card is available with either DB25 or 10-pin RJ-style
serial-interface connectors, and either RJ-11 or RJ-45 line-interface
connectors, on its interface (rear) module. It fills one function-card slot in
our MicroRacks (RM202, RM204, RM208, or RM216).
2.2 Features
Convenient rack-card design
Synchronous or asynchronous communication
Data rates up to 57.6 kbps, distances up to 20 miles (32.2 km)
2-wire/half-duplex or 4-wire/full- or half-duplex operation
Point-to-point or multipoint operation