Black Box ME801-C, Руководство пользователя

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8
SHORT-HAUL MODEM-B SYNC (SHM-B SYNC)
2. Introduction
The Short-Haul Modem-B Sync (SHM-B Sync for short)
is a synchronous full-duplex 4-wire line driver and
receiver that makes it possible for two RS-232-C devices
to communicate across distances up to 5 miles (8 km), at
data rates up to 19,200 bps. In addition to its transmitter
and receiver circuits, the SHM-B Sync also features status
LEDs, a loopback switch, and support for RS-232 clock
and control signals.
The SHM-B Sync is designed to operate with 4-wire
cable. See Appendix A for optimum cable specifications
and supported distances/data rates.
The SHM-B Sync is also designed for maximum
operator safety. There are no voltages greater than
12 VDC or 17 VAC present on the unit’s circuit board.
Opto-isolation circuits protect both the transmit and
receive lines against voltage surges (up to 20 VDC) such
as those caused by lightning.
The SHM-B Sync is available in either a 120-VAC
(ME801A) or 220-VAC (ME801A-E) standalone version
or a card version (ME801-C) that will fit in our ME810
or RM007 card chassis.