Hello, friend!
Please set ProfileBody/ Profile Parameters 25=60
Parameter 25:
Meaning: Duration of the timer in the ALERTING state
Range: 1 - (0xFFFFFFFF -1). The default value is 180(s).
1. Configure via web
Profile Parameters:
Set 25=60 & apply (save data)

2. Configure via OMCI / TR069
The relevant node:
InternetGatewayDevice.Services.VoiceService.x.VoiceProfile.{i}.xxxxxxxxxxxxxxx
Thanks!