Modify T38FaxMaxDatagram value

General Help
1

I’m trying to modify the T38FaxMaxDatagram value in order to resolve the following error when trying to send faxes:

UDPTL asked to send 146 bytes of IFP when far end only prepared to accept 93 bytes; data loss will occur.You may need to override the T38FaxMaxDatagram value for this endpoint in the channel driver configuration.

I’ve tried putting the following configuration parameter:
t38pt_udptl=yes,redundancy,maxdatagram=93
In the following places, with no change:
sip_general_custom.conf
In both the PEER and USER Details under Connectivity > Trunks for our SIP trunk
Added in “Other SIP Settings” Under Settings > Asterisk SIP Settings

I’m not quite sure where else to try

Running FreePBX 2.11.0.43

Thanks!

2

Actually, looking a bit closer, after adding
t38pt_udptl=yes,redundancy,maxdatagram=93
to
sip_general_custom.conf
a ‘sip show peer’ on the extension shows
T.38 MaxDtgrm: 93
However I still get the
UDPTL asked to send 146 bytes of IFP when far end only prepared to accept 93 bytes; data loss will occur
message

3

I would suggest upgrading FreePBX and Asterisk - that sounds like an Asterisk bug.

4

Well, we took it from 4.211.64-7 to 4.211.64-10 yesterday, but still the same issue. I guess I’ll spin up a test server of a supported version and see how that goes.