Fax Failures After Upgrade - Mitel 3300

[ralph]

Here's the Picture.
~40 clustered systems running 9.0
All faxes and modems work without issue.
Upgrade all systems to 5.0
Now no faxes work at all.

Now before anyone jumps on and says "Mitel has always said that faxes and modems aren't supported across IP trunks.  You have to have T.38"   
Screw that.  It all worked just fine and now doesn't after upgrade.   What changed?  Mitel Software.  Our Avaya systems don't have this problem.

But here's what I think I've discovered so far.   If I take my fax machine in my office and slow the xmit speed to 9600 it now works with out failure.   Now we can't expect people sending faxes to our customers to step down their transmit speed on their fax machines but if I have the customer knock their receive speed down to 9600 it appears to work without fail.

I'm sharing this because I'm sure that I'm not the only one with the issue.  I know there's a super double secret RTC command and script you can modify that may help be even Mitel says that 5.0 is the last version that will be supported.   And BTW.  Didn't help much.

So the solution seems to be to have the users step down their fax machines.   This can be a real challenge on some machines, even involving setting HEX codes.   But once done it appears to work.

Now for modem....

Ralph

PS.  Sorry for venting but this has happened to multiple customers of ours and Mitel's solution appears to be washing their hands of it because "Faxes and modems aren't supported." <add hang up here>

[Mitel100]

Hi Ralph, There are two things I would check, these would be:

1-Make sure all fax machines are in Zone 1
2-COS enable FAX setting


Other than that I have fax machines working on MCD 5.0 no problem, without T.38.

What are the fax machine connect to a 3300 or some kind of media gateway running SIP?

[ralph]

2-COS enable FAX setting

First I've heard of this one.   I'll check that out.
Perhaps I might of heard of is earlier if tech support didn't say "faxes are not supported across IP trunks <click>"

Ralph

[acejavelin]

I have seen this on a couple small clusters we have upgraded to 5.0... Faxes/modems worked before, without T.38, and not they don't, but not at every site. Two sites are networked over a hardware VPN over the public Internet (20-25ms ping times between controllers), both of those fail now where they worked before, and one site has direct fiber connection about 30 miles at 1GB (2-4ms ping times between controllers) and that works just fine. Tech support essentially gave me the same run around, "analog dial-up data services are not supported over IP trunks... <click>".

Guess I just chocked it up to the newer software has some different timings or uses to many system resources and causes these very time dependent connections to fail. Newer isn't always better I guess, but if you find a solution let me know. For these customers we essentially just made them use the PSTN trunks they have for those services, and it worked OK since they were very limited use devices.

[ralph]

I checked the fax options.   This is mainly for campon tones.  It is set to yes.

From the help files:

Camp-on Tone Security/FAX Machine
 Select "Yes" to prevent camp-on tone from being presented to a station. Although the camp-on feature is not disabled by selecting this option, any audible notification is disallowed and camp-on is applied without intrusion on the called party's line.
 No
 
External Trunk Standard Ringback
 Select "Yes" to return a single ring cadence on a trunk. Enable this feature when a trunk is used for modem dial-in access as the external double ring cadence is often detected as a busy by the modem.

Enable for Tie trunks to override the Ringing Cadence for Tie Line Calls setting in the Display of DASS OLI/TLI information requires that the ANI/DNIS field be enabled. form.
 No
 
Return Disconnect Tone When Far End Party Clears
 Select "Yes" to return busy tone instead of dial tone when the far end hangs up. This option is commonly used for analog devices such as FAX machines to prevent them  from remaining in an off-hook state after an incoming call is ended.
 No
 

[Mattmayn]

Ralph, I have always claimed that the releases after 9.0 intentionally broke the T.38 faxing to sell licensing and DSP IIs. They did work just fine with 9.0 and below and then suddenly they don't. They also had a hard time making the T.38 work when that licensing came out. They sent an engineer to one of my customer's sites to do testing on Mitel's dime. The releases after that work much better, if you have the licensing for it.

We use SIP ATAs for faxes now unless they need heavy fax usage. Then they just get a POTS line to avoid the headache that is T.38 over IP trunks.

[ralph]

We use SIP ATAs for faxes now unless they need heavy fax usage. Then they just get a POTS line to avoid the headache that is T.38 over IP trunks.]We use SIP ATAs for faxes now unless they need heavy fax usage. Then they just get a POTS line to avoid the headache that is T.38 over IP trunks.

Which devices are you using?

Ralph

[Mattmayn]

We use Europa Vegastreams.