Rockwell Automation 1771-DA,D17716.5.13 U MNL 1771-DA ASCII I/O MODULE - Manual (Page 259)

Specifications
Appendix D
DĆ3
RS-232-C Specifications
Receiver Circuit, Control:
(pins 4, 7, and 20)
Isolation:
500Vdc between customer and
PC system circuitry
Typical Input Voltage Range:
+3 to +25Vdc for Request to
Send or Data Terminal Ready
-3 to -25Vdc for signal inhibit
Typical Input Impedance:
3k to 7k ohms for +3 to +25Vdc,
and -3 to -25Vdc
Receiver Circuit, Data:
(pins 2 and 7)
Isolation:
500Vdc between customer and
PC system circuitry
Typical Input Voltage Range:
+3 to +25Vdc for space state
-3 to -25Vdc for mark state
Typical Input Impedance:
3k to 7k ohms for +3 to +25Vdc,
and -3 to -25Vdc
Transmitter Circuit:
(pins 3, 5, 6, and 7)
Isolation:
500Vdc between customer and
PC system circuitry
Output Voltage Range:
+5 to +15Vdc for space state
-5 to -15Vdc for mark state