DB9 pinout

[RRMerlin]

IN EFIS D100 installation guide page 2-2, the serial interface female DB9 is showed with pin 2 = TX and pin 3 = RX. On a regular RS232 DB9, it is the opposite. As D100 pin 22 is RX, it is logical that DB9 pin 3 would be TX as in the regular RS232 DB9 pinout.

 

[dynonsupport]

It's actually calling out the Dynon-side function. They are pinned out with the standard RS-232 way, but so you don't need a null modem. So it's pinned out so that when you have a device with a standard 9 pin serial connector, it just works.