We have one remote office is uisng FXS module (VIC3-4FXS/DID) to connect to their fax machine. The issue is sometimes they have problem to send out or receive the fax, sometimes they only can receive around 30% fax document from customer. The problem is inconsistance.
We use the CUCM 6.1 to set it up, are there any configuration I should add in CUCM or router could resolve this issue? Or how to do the troubleshooting?