Mitel T.38 FAX negotiation.

[pradeepgali]

I have the fax with G.711 codec working fine. the customer requirement is to make the FAX calls using T.38 codec. I the FAX Service Profile > Intra-Zone Fax Service Profile for T.38 as shown in attached figure(Tried with Profile 2 and 3) and and selected the same profile in Network Zones.  Allowed the T.38 codec in Codec Settings.

I still see Mitel 3300 is not negotiating to T.38 FAX and FAX is working with G.711. I wan to force Mitel 3300 to negotiate with T.38 for FAX. Can suggestions and inputs?

[johnp]

T.38 requires licenses and DSP II card I believe, that is to analog ports. I think a T.38 call to a sip ata that supports T.38 would renegotiate.

[pradeepgali]

I have 4 licenses and also have DSP card which i was connected for faxing. Right now i have G.711 FAXing working fine. Do i need different DSP card from T.38 Faxing from the car i have?

[pradeepgali]

Please find the DSP card image i am using below

[pradeepgali]

Please find the attached T.38 FAX Licenses image

[lundah]

Please find the DSP card image i am using below

That's not a DSP card. Look in Hardware Modules for an inventory of what you have installed.

[pradeepgali]

I am not sure where to look for DSP card. We had this T.38 faxing working with the same hardware a year back. Now with the latest software version, i am not sure why i am not able to send the T.38 FAX.

Please let me know if there is any way to make sure if i have the proper hardware for T.38 faxing.

As i mentioned earlier, i have T.38 fax license and hardware(Not sure how to check). I allowed T.38 codec in (Codec Settings), Configured Network Zone to T.38 FAX profile(I have attached in my previous posts showing T.38 FAX configuration).

[pradeepgali]

Is there anything we need to enable in COS for T.38 FAXING?

[wiseguy]

Yes, the COS settings are the trigger to get T38 working. What version are you on?

[lundah]

The DSP modules are MMC cards installed on the mainboard of the controller. There's no way physically see if they're installed without opening up the controller chassis, which is why I recommended looking at the Hardware Modules form as that tells you what MMC cards are installed.

[pradeepgali]

After enabling the FAX in COS, i see Mitel is sending T.38 codec in initial INVITE. After the voice call is connected the FAX is working using G.711 Codec. If i disable multiple m-lines in SIP Peer Profile > SDP, then i see Mitel is sending INVITE message for negotiating to T.38 FAX and the FAX works using T.38 Codec.

We are looking for the reason why there is no negotiation from Mitel 3300 for T.38 FAX when "Allow peer to use multiple Active M-Lines"  is set to "Yes".

[lundah]

I'd guess you'd have to open a tech support ticket with Mitel to get an answer on that one.