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 synchronous↔asynchronous 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
