Fax passthrough and the Grandstream HT-503

Does anybody who has fax passthrough working with the Grandstream HT-503 care to share their configuration(s) with me?

We are running an Asterisk installation with an 24-channel T1 running into a Digium TE120P installed in a Linux server. We are running asterisk 1.4.11 (yes I know we should update.)

We previously had our fax machine connected to a Grandstream HT-488, which worked without problem until the HT-488 quit receiving faxes. There is another fax machine in the building that also uses an HT-488, and it works fine (knock on wood) and I believe I have the configuration matched up to it as best as possible, but it seems as if the HT-503 answers the call and connects briefly to the fax machine, but then spins its wheels. If I take the HT-488 from the other fax machine and hook it up it works (after changing the account info of course) no problem.

Thanks for any help in this matter. I also have a sipura3102 that I’m trying to get working with the fax machine, but the configuration on that thing is like from another planet compared to the relatively simple configuration options on the HT-488.

Sounds to me like you just have a damaged unit.

Check to see if there is updated firmware, and install it if there is. If not, just replace it.

I had been considering that possibility. I guess at this point, it’s my best option, as I have already upgraded the firmware.