..\Manuals\RCI-100-MDM rev.B.doc
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MDM Communication Option:
The -MDM communications option to the RCI series utilizes a 2400-BAUD modem to exchange the
signal data between a host and its remote(s). There are two types of
Operating Modes
that can be
configured: 1) Answer-Only and 2) Answer-and-Originate.
In
Answer-Only
mode the RCI-100-MDM will only answer incoming calls. It will not initiate calls to
other devices. This is useful when only periodic data exchange is required. Typically a computer or
PLC places a telephone call via a standard modem, the RCI-100-MDM answers and the two can now
exchange data until the computer or PLC terminates the call.
In
Answer-and-Originate
mode the RCI-100-MDM operates just like in the Answer-Only mode with the
additional capability of placing a call to another RCI-100-MDM or to a computer or PLC. A
configuration procedure allows the programming of events or time intervals when the RCI-100-MDM is
to place a call. This is useful where unattended, periodic data exchange is necessary. It is also useful
when long distance charges apply to a call since the units can be programmed to communicate only
when there is a change of status at one site or the other. Both units can be programmed to operate in
the Answer-and-Originate mode thus providing bi-directional status change updates.
Modem configuration is done via a bank of DIP switches. The switches are located on the
communications board just to the left of the telephone jack. They are either a slanted rocker type that
flips
up for OFF
and
down for ON
or a flat rocker type that are marked
OPEN for OFF
and/or
CLOSED for ON
.
In Answer-Only mode, SW1 is used exclusively to set
all operating parameters (see Answer-Only Mode
Configuration below). In Answer-and-Originate
mode, SW1 is not used and all switches must be in
the OFF position. Instead the RS-232 connection is
used to exchange a configuration file with a PC or
laptop. This is necessary because of the large
number of parameters that are required to be
configurable for flexible dialing operation (see
Answer-and-Originate Mode Configuration below).
Answer-and-Originate Topologies:
The -MDM communications option to the RCI series utilizes dial-up telephone transmissions to
exchange the signal data between a host and its remote(s). There are two types of
Topologies
that
can be configured: 1) Point-to-Point and 2) Host-to-Multipoint.
In a
Point-to-Point
topology one host
communicates with one
remote. The two
exchange all their
signals with one another.
The remote is configured
as remote #1 even
though it is the only remote in the system.
