Hi,
First let me explain the configuration at the client site :
3cx server with the latest update V15.5 sp6
8 grandstream gxp2160 phones with firmware 1.0.9.102, the latest.
1 Gigaset N510 ip pro base station
4 gigaset R650H portables connected to the N510.
5 of the gxp21060 are in...