GRT Avionics

I am trying to use 2 different serial outputs to talk to different devices. Serial out 4 is air data Z and serial out 7 is air data D. When I set out 4 it turns off out 7 and if I turn on 7 it turns off 4. How can I use both?

This sounds strange, I would call GRT.
But first (they will want to know), double check the wiring. Then,
When port 7 is on, does the device it's sending data to get it?
When port 4 is on, does the device it's sending data to get it?
Can you turn them both on (and stay on) if you change one format to something else?

Bob, thanks for the reply.
I know the wiring is good.
If I turn on serial output 7 my G327 stops showing the altitude immediately.
If I turn on serial output 4 the King 90B shows NO 232 DATA.
When I turn on both outputs to Shadin Z I get a serial port conflict message.
The King 90B will eat Shadin Z so I guess I will have to splice the 232 data in wire to the GRT serial out 4.
Thanks
-Rob

I have never read of any restrictions on using the same, or different, formats on different ports. I would call GRT.

The "Fuel/Air Data" outputs are all driven by the same software and you can only have one active at a time. The conflict message is missing for the D format.