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CHAPTER 2: Introduction
2. Introduction
The SHM-NPR Plus (Short-Haul Modem [Nonpowered]
Plus) is intended to be used for local data distribution:
Two of them carry asynchronous communication between
computers and terminals. The SHM-NPR Plus operates
full-duplex over two twisted pairs or a single coax line.
Figure 2-1 below shows a typical application.
You can strap the SHM-NPR Plus’s transmit carrier to be
constantly on or to follow (be controlled by) the DTR
signal. In controlled operation, the local SHM-NPR Plus
raises carrier as soon as it sees DTR from the local DTE;
when the remote SHM-NPR Plus sees carrier, it raises DSR
Figure 2-1. Typical application.
SHM-
NPR
Plus
SHM-
NPR
Plus
Single Twisted Pair or
Single Coax Cable
Computer or
Data PABX
with Async
Comm Port
Computer or
Terminal with
Async Comm
Port
