Hi all, I'm setting up a fax line for the first time for a customer. I host the PBX and their extensions connect through an SBC running on a Raspberry Pi. I have set up a Cisco SPA112 for the fax machine. I can get the extension to register with 3CX, I can get the fax machine to call my mobile phone, I can get the fax machine to send a fax to my virtual fax provided by efax.com.au but when testing it with the client I ask him to send some faxes to the people he would normally fax, but it does not work. The fax machine does not give any error, it just keep retrying. I have done a lot of reading and there are plenty of people saying that it won't work, it can't work, etc etc, however, it worked perfectly for the customer every single time when he had it plugged directly into the voice/fax port (the UNI-V port) of the NTD (the customer has fibre and the NTD is the box on the wall that the router and/or phones/fax plug into, depending on configuration). If Telstra can make it work over their UNI-V port, then surely we can make it work through a Cisco SPA112. Our SIP provider supports G711a, G711u, G722, and G729. From anyone who is actually using a fax through 3CX, what codec are you using, what ATA are you using and what other tricks did you use to get it working reliably?