General Settings>Alerts>Call Alert Tone Duration>10 seconds
Accessories>GPIO Physical Pins>GPIO2>External Alarm/Horns and Lights, Active level High
Accessories>Horn and Lights>Alarm> Permanent Ext Alarm, Duration 10 Seconds, Delay 0
Control Buttons, unassign everything so nobody can screw with settings. This is just a personal preference.
Systems>QCII Systems> System Name is dealers choice, Call type is Call alert w/voice, Call format A-B/Long B
the rest of the settings here are whatever tones your department uses.
Since you say it activates on the radio itself, I would look at GPIO pin settings and your relay wiring which is most likely the problem.
Wiring for the relay goes red to pin 4. Red should be in tab on left. Black(ground) goes to pin 7. Black goes to right tab on relay. A jumper wire goes from this same to tab to bottom tab on relay. Top tab is the wire that goes to your PA system.
The bottom of the relay is the side with the screw tab on it.