CSE Kingfisher PLUS+, Hardware Reference Manual

Page: 31 / 89

Superseded Hardware Manual 7.12 Page 31
1.7 LM-2: Lin e Mo d e m Mo d u le , Du a l Le a s e d Lin e 2-Wire
The LM-2 line modem module provides a telephone line interface and data exchange functions for
remotely connected units over leased circuits. This module is equipped with two ports that may be
used simultaneously. The integral modems are standard V22BIS devices allowing speeds up to
1200 bps. Using this module simplifies the user interface in that a great deal of the setup procedure
has been eliminated.
The LM-2 modules primary function is to provide a leased line interface to two separate telephone
lines into the RTU at speeds up to 1200 bps. All communications flow control is managed by the CP-1
or SBX-2 processor module. This module cannot be used by itself (i.e. it must be used with a
processor module).
The module also incorporates dual RJ45 connectors to allow use with external radio transceivers up to
1200 bps in CCITT V23 mode. This is a non-isolated interface and therefore must be close coupled
with a compatible transceiver if used. The 0 V of the radio must be connected to the 0 V of the
backplane.
Red LEDs on the front bezel show the status of data transfer, for port 1 and port 2. A green LED at the
top of the faceplate labelled OK is ON when the module is operating correctly. This module consumes
power from +5 VDC bus on the backplane. The module can be installed in any I/O slot of a 6 or 12 slot
backplane and in slot no. 3 of a BA-3 backplane and any slot except slot 1 of a BA-4 backplane. Up to
four modem modules can be installed in an RTU system.