GPS2 and TELEM uart port

hello everybody,
i’m setting all the same parameters for both serial ports as:
serialx_protocol → 10
serialx_baud–> 57
serialx_option → 4
to monitor telemetry through FRSKY transmitter.
Why using telem2 everything is working while using gps2 port i did not receive any data?
is there other parameters which i do not know?

Serial1-> Telem1
Serial2 → Telem2
Serial3 → GPS1
Serial4 → GPS2

yes as you write i set:
serial2_protocol to 10
serial2_baud to 57
serial2_option to 4
serial4_protocol to 10
serial4_baud to 57
serial4_option to 4
if i connect the cable to the telem2 port FRSKY telemetry on my taranis is working
if i connect the cable to the GPS2 port Telemetry does not work.

I suspect a wiring issue.
Telem1 and Telem2 have RTS and CTS wires, the GPS ports dont. That could be confusing the issue.
It might possible your GPS port doesnt support the option 4 too.

RTS and CTS connection are not used. The connector only uses first three pin and the last one.
So VCC, TX, RX, GND are being used.
Both port are suitable to use option 4 following pixhawk namual. I even changed this parameter but it still not work.
I’m wondering why??

What flight controller have you got?
Share a param file.

miniquad_2_paramlist_11092022.param (18.6 KB)

here’s the parameter list…