PSTN calls dropping intermittendly

Please can someone shed some light on why calls incoming and out going on PSTN lines are disconnecting intermittendly there is no exact time limit.

I have looked for config files that have info on time limit etc but cant find anything.
:frowning:

what kind of interface card are you using? run zttool adn see if you are getting missed interupts

I am using a digium TDM 400P Card with 4 analog ports (2 used) my phones are act 106 and sipura spa 841. I see there are no interupts missing.
Can you think of thing else