Has any had a problem with Sip trunks dropping calls it's only the out side party. Calls up 7 to 20 mins.
CP 20 Nec Sip.
Jim
Carrier, Internet connect or network (router etc) are your most likely culprits. You will need to wireshark it but if you are only looking at the phone system you probably won't find the issue.
Try this, check and possibly extend the UDP timer in the router.