Aviom 6416dio - Manual (Page 85)

75 rs-232/422
RS-232/422 Pinout Information
Aviom® Pro64™ products can use Virtual Data Cables™ to transmit and receive
user control data over RS‑232 and/or RS‑422. (RS‑422 is not supported on
every Pro64 product.)
The following table shows the pinout of the RS‑232/422 jack. Note that in
the pinout table, some transmit/receive functions (abbreviated as Tx/Rx) are
different for RS‑232 versus RS‑422.
Pin Function
1 No Connect
2 –Rx (RS‑232), –Tx (RS‑422)
3 –Tx (RS‑232), –Rx (RS‑422)
4 +Rx (RS‑422)
5 Ground
6 +Tx (RS‑422)
7 No Connect
8 No Connect
9 Ground
Cables for RS-232/422 Applications
DB9 cables are available with male‑to‑male, female‑to‑female, and male‑
to‑female connectors. Aviom’s RS‑232/422 port uses a male DB9 connector
and therefore requires a cable with a female connector. The format of the
connector at the other end of the cable (male/female) is dependent upon the
equipment being connected to. However, connection to other equipment
will usually require a female‑to‑female cable.
There are many different types of DB9 cables available, but Aviom selected
a pinout for our DB9 connector that would allow both RS‑232 and RS‑422
connections to be made with off‑the‑shelf cables. A “null modem” cable
should be used in RS‑232 mode. Unfortunately, there are several different
types of cables referred to as null modem cables. A true null modem cable
crosses pins 2 & 3, 4 & 6, and 7 & 8. Pin 5 will be connected straight through,
but pins 1 and 9 will not (though pin 1 will be connected to pin 6 at each
end). An example of this type of cable is the L‑Com® CSNULL9FF‑XA (where X
= cable length).
An example of the type of null modem cable that should be avoided is the
L‑Com CSNULL9FF‑X (where X = cable length). This is a straight‑through cable