PortTech 370 dont recognise cellular phone switched off

[AndreaL]

I hawe a PorTech 370 with latest firmware that is working in both directions. The only problem remaining is that when a mobile phone is swithed off and i try to call it, 3cx do not know that the phone is off and continue making the calling tone "tooo, tooo"
Any Ideas? :x

 

[AndreaL]

I found the problem...

Go on Sip Settings and switch to on the 183 parameter.