Specifications

Copyright © AMETEK
16
16.1 Description
The Low Speed Data (232) Module provides two
RS-232 data circuits, or channels, over which you
can transmit and receive data and/or modem
control signals at speeds of 0 to 9600 bps asynch.
You do not have to preselect the data rates. The
two circuits operate independently of each other,
simultaneously carrying their data/control signals
over two FOCUS DS0 channels, or time slots.
The 232 module does not process the data passing
through it. Data and modem control signals, such
as those in Table 16-1, are transferred transpar-
ently across the FOCUS DS0 channels.
As Table 16-1 shows, the module supports CTS,
RTS, DTR, and DSR handshake lines. (Note: A
10ms idle period on the data line is required to
transfer handshake changes.)
The module’s interface gives you two DB9 female
connectors, one for each channel, for directly
connecting your RS-232C equipment.
16.2 Application
The Low Speed Data (232) Module’s two inde-
pendent channels and transparent RS-232C
communication capability give you a wide assort-
ment of useful applications. You can connect
modems and other communication devices to each
channel independently.
You can use either or both of the module’s
channels for Supervisory Control and Data
Acquisition (SCADA) and other data terminal
communications requirements. The module is
especially useful when extension of the SCADA
communications lines to remote sites is inconve-
nient or expensive. The two most typical types of
application are 1) connecting remote terminal
units (RTUs) from remote locations to a master
and 2) connecting other types of terminal
equipment (microcomputers, event recorders,
modems, etc.) from one remote site to another.
Typical devices you can connect to the module
include:
• An RTU
•Amodem you want to connect to fiber
optic cables across T1/E1
•A“smart switch” or port switcher
•Aremote (e.g., miles apart) hard drive,
printer, or server
• Mirrored-bits applications for SEL

relays
16.2.1 Typical RS-232 Application
Figure 16-1 shows a typical RS-232 application.
Substation A is a conventional installation with a
remote terminal unit (RTU) connected to the
system SCADA line via a modem. Substations B
and C are linked by FOCUS. The RTU in
Substation B is linked to the SCADA line in the
usual manner. Substation C’s RTU, however, is
linked through channel A on the FOCUS T1/E1
line to the SCADA line via a second modem at
Substation B. This eliminates the need to extend
the SCADA line to Substation C.
16.2.2 Connection to SEL Relays
The pin-outs for connection to relays SEL
2020/2030, 2100, 300 & 400 are shown in Figure
16-6.
16. Low Speed Data (232) Module
TX Transmit Data
RX Receive Data
RTS Request to Send
CTS Clear to Send
DSR Data Set Ready
DTR Data Terminal
Table 16–1.
Data & Modem Control Signals Supported.