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CHAPTER 2: Introduction
2. Introduction
2.1 Overview
The Async Short-Haul Modem MP is equipped with a virtual wish list of “bells and
whistles.” Point-to-point or multipoint applications are supported. Two separate
control signals may be passed (one each way), each with switch-selectable pin
assignments. Data lines are protected from ground loops and electrically volatile
environments by optical isolation and Silicon Avalanche Diodes. System integrity
can be evaluated using two built-in test modes: local analog loopback and remote
analog loopback. Tri-state LEDs monitor transmit data, receive data, and control
signals. Finally, 4-wire connections may be made using either RJ-11 jack or terminal
blocks—both are included.
In addition, the Async Short-Haul Modem MP is perfect for low-power RS-232
environments. The Modem is AC powered, and therefore is the recommended
solution for RS-232 environments whose interface voltages are below RS-232
specifications. The Modem supports data rates to 115.2 kbps and extends RS-232
transmission distances up to 14 miles (22.5 km) over two twisted pairs.
The Modem is housed in a sturdy metal case and comes with either 115 or 220V
external transformers.
2.2 Features
• Data rates to 115.2 kbps.
• Built-in optical isolation and high-speed surge protection.
• Distances up to 14 miles (19 AWG TWP @ 1200 bps).
• Tri-state LED indicators.
• Point-to-point or multipoint applications.
• Local and remote loopback test modes.
• DCE/DTE switch-selectable.
• Hardware and software flow control support.
• Externally powered.
