I have an asterisk system with a TDM800P installed.The system is operating quite well. But occasionally, when a caller from PSTN call to a number attached to TDM800P, they just get ringing tone while asterisk CLI information show that DAHDI has anwsered the call and forward the call to an IVR.
The problem happens occasionally, most of the time TDM800P can answer the incoming call correctly and user hear the IVR. About 10 percent of PSTN caller encounter the problem as described.
Please kindly recommend me what to do to solve this problem.