Panasonic KX-TR320EXF Service Manual page 28

Selecting CH1
21.1.1. RF Output Is Not Output To ANT Terminal.
21.1.2. Modulation Does Not Work In Transmission.
21.2. Transmission Trouble/ AF Circuit
Condition
Channel No. Setup
Standard Modulation (1KHz) Input
C3V Applied
MIC Input Check
TXP (3V): Pin11 (CN5)
TX (LOW): Pin12 (CN5)
21.2.1. Modulation Does Not Work.