Documentation Number 3PCIOSD1x-3903m Manual
Appendix B
B-1
B&B Electronics Mfg Co – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics Ltd – Westlink Comm. Pk. – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445
Appendix
B:
RS-232 & RS-422/485 Pinouts
Table 1: RS-232 Pinouts
With 2-wire RS-485 mode operation, your connection cable must
jumper TD(A) to RD(A) and TD(B) to RD(B). Connect from TD(A)
and TD(B) to the Data A(
−
) and Data B(+) wires of your RS-485
network.
Note that the EIA RS-422 Specification labels data lines with an "A"
and "B" designator. Some RS-422 equipment uses a "
−
" and "+"
designator. In almost all cases, the "A" line is the equivalent of the
"
−
" line and the "B" line is the equivalent of the "+" line.
More
information on RS-422 communications can be found in our free
RS-
422/485 Application Not
e (available on our websites).
Name Description Direction
DB25M
Pin
Shield Shield
------
1
TD Transmit
Data Output 2
RD Receive
Data Input 3
RTS Request
to
Send Output 4
CTS Clear
to
Send Input 5
DSR
Data Set Ready
Input
6
GND Signal
Ground ------ 7
DCD Data
Carrier
Detect Input
8
DTR Data
Terminal
Ready Output
20
Table 2: RS-422/485 Pinouts
Name Description
Direction
DB25M
Pin
Shield Shield ------
1
TD (A)
−
Transmit Data A
Output
2
RD (A)
−
Receive Data A
Input
3
GND Signal
Ground ------ 7
TD (B) +
Transmit Data B
Output
14
RD (B) +
Receive Data B
Input
16
B-2
Appendix B
Documentation Number 3PCIOSD1x-3903m Manual
B&B Electronics Mfg Co – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics Ltd – Westlink Comm. Pk. – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445
