Fax Machine Radio Button on Phone ports 1

[Nortel4Ever]

Can anyone tell me what the Fax Machine radio button on analog Phone ports actually does? I have been working with IPOs and connecting fax machines to Phone ports since release 7.0 software (at the time of Nortel's demise). I've never had to use the Fax Machine option, I've always just used the default Standard Telephone and have had no issues.
This past week I could not get a fax machine to send or receive on a 11.0.3 IPO500V2 with PRI (real PRI, not SIP based)using a Phone port on a Combo card. Having nothing else to try I selected the Fax Machine option and WTF, now the fax maching sends/receives just fine. The Help option really doesn't say much:

"If fax Relay is being used, this setting should be selected on any analog extension connected to an analog fax machine. This setting can also be used with SIP trunks. "

I really have no idea what this setting actually changes.

 

[snowman50]

I suppose I have been the opposite to you and always set them up with fax option.
It was there so I used it..

I think I tried it once without it and didn’t work properly..so changed to fax option..

 

[biv343]

I always set them to standard telephone, test things out, then switch to fax machine if there are fax issues. I'd guess 98% of the analog ports with fax machines connected are set as standard telephone and the other 20% are set as fax machine.

If that doesn't work, then its time to make a sacrifice to the Gods of faxing and start messing with the fax machine itself. Thankfully most faxing in my patch is migrating to cloud based fax services, so fax headaches aren't as prevalent as they once were.