AS5300 to channel bank

We have a config where we are replacing an international T1 circuit with 2 AS5300s and running VoIP for our connection between a PBX and a channel bank. Unfortunally the AS5300 is regenerating the dialtone when in our case with have operators with headsets that are simply waiting for the PBX to place a call to them (innbound to the channel bank only).

Any ideas what can be done to suppress the dialone? The T1 setup is AMI/SF E&M Wink to the channel bank.