1. Check the PRA configuration, it was correct, the same with other two E1s.
2. Capture call logs on U1980, find out the failed call, in the failed call, U1980 received a PROGRESS, and it said ” Invalid number format (address incomplete)”
3. Then collect a successful call on other E1, and compared the Setup message with the failed calls, and the caller number/called number/call type is the same.
4. Capture the incoming successful call , checked the Setup message , and found the caller number type is : National number, the called number type is: Unknown
5. Modify this PRA trunk caller type to National number, and called number type to Unknown, the issue persist.
6. Check with Customer what is the call type PSTN needed, but they cannot provide due to the device in PSTN is too old.
7. Then try to modify other caller type, then issue was resolved when the caller and called number have Unknown type, the modify command is :
#config protocol pra officeno 250 typeofcldnumber unknown typeofclinumber unknown