Pixhawk wifi module


I am using the Pixhawk 4 of Holybro and MAVLink WiFi Bridge.
wifi bridge

I want to connect wifi bridge to TELEM2 of Pixhawk4.
and Wifi bridge’s manual says that

SERIAL2_PROTOCOL = 2(MAVLink2) or 1 (MAVLink1)
SERIAL2_BAUD = 921 (921600 baud)

so, I set SERIAL2_BAUD = 921600. But, I can’t find SERIAL2_PROTOCOL.
I checked the Parameter Reference, but it’s not existed.

How can I connect between pixhawk4 and wifi bridge?

thank you for your time.