Confused on analog Fax configuration

I am a novice and I inherited a “working” Trixbox - Asterisk - FreePBX system

I have figured out that to create normal voicemail users - you create their "extension"
and then use Endpoint Manager to link the phone MacID to the new extension

so far so good…

There are also about 3 faxes (which I think are using a Cisco ATA-186 to get the analog dialtone then are connected directly to the phone port on the fax)

One of these stopped working just the past day. The server was restarted but
if that caused the problem I don’t know what I should be looking for.

I don’t know about the other fax extensions. They are not nearby. I am concentrating on getting 6754 working again.

These 3 “faxes” have extensions in FreePBX but there is no connection to the MAC IDs of the ATA devices, in fact the extensions don’t show in Endpoint manager

The only thing I can see which is different on the FreePBX extension configuration is they each read Dial: CUSTOM/6754 or CUSTOM/5725 whatever the extension #.

The normal voicemail users have a Dial: SIP/5707 matching their extension. There is some configuration information in SIP_Additional.conf for all the voicemail users. However none of the “FAX” numbers have anything entered in this conf file (I checked an older version and these numbers were skipped as well, so the CUSTOM/xxxx must be configured somewhere else.

I just cannot figure out how the faxes are configured and what can I do to troubleshoot. The MACID shows up on the switch port mac table so I have no reason to think the ATA is defective. I am guessing it is something to do with SIP and communication

Thanks in Advance

Tom Gilbert - TomBexarMet