Line disconnection while on call

[Tripoth]

SIP trunks on a MiVoice 250


While speaking with someone on the phone for an extended period of time the call gets disconnected.

The SIP carrier sees the caller(person calling in) disconnecting the call. Not his Trunk dropping on his own.
I have a ticket in with the data group to check on the QOS and such on their end.
I am just wondering if there is a flag or timer that might cause such an issue on the 250?

[NEPhoneGuy]

Does this happen with every call or just to certain parties? If the carrier sees it on the far end not much you can do about that if that really is the case. If it's on every call I'd push for your carrier to open some tickets upstream, even if to a single site they should be able to investigate back with a ticket of their own. If just a single number could be the far end's provider or phone system.