Alcatel

The Alcatel-Lucent OmniPCX Office doesn’t fully comply with the RFC (session timer issue), which causes the system to disconnect after 15 minutes.

How can I prevent this from happening?

To fix this, go to the Expert options in the advanced settings of your SIP trunk and add the following value:

session-timers=refuse

KPN markets the Alcatel-Lucent OmniPCX Office under the name Vox Novo Office. It’s essentially the same system but branded differently.