I have a site with a Paxton net2, it is registered as a sip device and calls present to it, bit when answering said calls on polycom phones the call is dropped so no speech and no ability to release the door. (Audio and door control work through the Paxton video units). The net2 did work with polycom phones when the door entry was on its own ADSL, but this has been moved over to the phone fttc line with a draytek router (dos defence is off so UDP flood defence also disabled) any ideas what is causing the calls to drop and how to fix it? The phone support team looked at the call attempts and deemed it was the Paxton not handing reinvites as the calls hit a hunt group of users.