Documentation Number: 3PCI-MIport-4004qsg
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EIA-232-E (RS-232)
Function
PIN #
DB-
25
DB-
9
TO
DTE
TO
DCE
Shield 1
Transmit Data (TD)
2
3
>
Receive Data (RD)
3
2
<
Request To Send
(RTS)
4 7 >
Clear To Send (CTS)
5
8
<
DCE Ready (DSR)
6
6
<
Signal Ground (SG)
7
5
Received Line Signal
Detector (DCD)
8 1 <
DTE Ready (DTR)
20
4
>
Ring Indicator
22
9
-----
THRESHOLD VOLTAGES
Signal with
Respect to SG
Signal A with Respect to
Signal B
Signal A with Respect to
Signal B
SIGNAL
STATE
RS-232
RS-422
RS-485
"0", Asserted, ON,
Space, Active
+3 to +25 VDC
+2 to +6 VDC (Transmitter)
+0.2 to +7 VDC (Receiver)
+1.5 to +6 VDC (Transmitter)
+0.2 to +12 VDC (Receiver)
"1", Disasserted,
OFF, Mark, Inactive
-3 to -25 VDC
-2 to -6 VDC (Transmitter)
-0.2 to -7 VDC (Receiver)
-1.5 to -6 VDC (Transmitter)
-0.2 to -7 VDC (Receiver)
NOTE: Some RS-422 and RS-485 equipment use "+" and "-" descriptors.
The "-" corresponds to "A" and the "+" corresponds to "B".
