@SurferPupThank you for the update. Please share your steps so other members can benifit for your experience.
The HP8620 passes the printer fax test plugged into a Cisco SPA112 ATA. I can hear the Australian dial tone and my phone number ringing tones. However when someone sends me a fax it fails and trying to phone it from my mobile phone there is silence for 30 seconds followed by an Optus message, “This number is unavailable...” When I try to send a fax, it rings and connects but will not transmit the fax. I’m guessing there are one or two settings that need changing. I have tried many variations. Does anyone have a suggestion on the correct configuration? Thank you for any suggestions as your help has gotten me this far.