We want to route Incoming PSTN call to SIP Server, for that we are using AS5300 with CAC Access Bank 1 which is having 1 FXS and 1 FXO card. AS5300 is connected with Access bank via T1 interface. And PSTN line is connected to FXO port on Access Bank. Upon dialing local PSTN number, only one ring is heard and dead silence thereafter. Can anybody please let us know what is wrong.