the pins are numbered 1 to 8 from left to right with the tab down.

Here are the RS232 pin assignments :

1-dcd 2-rts 3-dsr 4-txd 5-rxd 6-gnd 7-cts 8-dtr

Note: pinouts are printed on the bottom of the units and also within the user Manual

Here are the typical pin numbers and color codes for a db25 to rj45 mod-tap kit.

1-blue 2-orange 3-black 4-red 5-green 6-yellow 7-brown 8-white.

More detailed pinout diagrams can be found in the User Guide or from the Perle Website link below.

On some versions of the Iolan the manual and pinout labels are incorrect for the RS422 model. Here are the correct RS422 pin specs for the IOLAN+ (same for the Jetstream).

Pin Description Direction
1 No connection
2 Signal Ground
3 RXD - RDA Input ( <-- )
4 TXD - TDA Output ( --> )
5 TXD+ TDB Output ( --> )
6 RXD+ RDB Input ( <-- )
7 No connection
8 Signal Ground

Note: The IOLAN+ and the Jetstream use a common ground therefore be sure to use at least one of the signal grounds.