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ROC800-Series Instruction Manual
5-10
Communications
Revised Jul-14
Built-in
– Comm2 EIA-232 (RS-232C).
Module
– Comm3 to Comm5 EIA-232 (RS-232C).
EIA-232 (RS-232) uses point-to-point asynchronous serial
communication and is commonly used to provide the physical interface
for connecting serial devices, such as gas chromatographs and radios to
the ROC800-Series. EIA-232 (RS-232) communication provides
essential hand-shaking lines required for radio communication, such as
DTR and RTS.
EIA-232 (RS-232) communication includes LED indicators that display
the status of the Receive (RX), Transmit (TX), Data Terminal Ready
(DTR), and Ready To Send (RTS) control lines.
Table 5-6
defines the built-in EIA-232 (RS-232) terminals at the
Comm2 port and their function signals.
Table 5-6. Built-in EIA-232 (RS-232) Signal Routing – Comm2
Signal
LED Function
Terminal
RX
Lit when Comm2 is currently receiving.
1
TX
Lit when Comm2 is currently transmitting.
2
RTS
Lit when Comm2 request to send is active.
3
DTR
Lit when Comm2 data terminal ready is active.
4
GND
Common.
5
The EIA-232 (RS-232) communication module provides EIA-232 (RS-
232C) signals on the Comm3, Comm4, or Comm5 port depending on
where you have installed the module. Refer to
Table 5-7
.
Table 5-7. EIA-232 (RS-232) Communication Module Signal Routing – Comm3, Comm4, and
Comm5
Signal
LED Function
Terminal
RX
Lit when module (Comm3, Comm4, or Comm5) is
currently receiving.
1
TX
Lit when module (Comm3, Comm4, or Comm5) is
currently transmitting.
2
RTS
Lit when module (Comm3, Comm4, or Comm5)
request to send is active.
3
DTR
Lit when module (Comm3, Comm4, or Comm5)
data terminal ready is active.
4
GND
Common.
5
5.8 EIA-422/485 (RS-422/485) Serial Communications Module
EIA-422/485 (RS-422/485) communication modules meet all EIA-
422/485 (RS-422/485) specifications for differential, asynchronous
serial communication transmissions of data over distances of up to 1220
meters (4000 feet). EIA-485 (RS-485) communication is commonly