fax:Relay modem:off vs. fax:Relay modem:PT 1

[ShikePoke]

CMs8700 with CM release 4.0.1.731.2.

From anywhere, faxes work fine fax to fax machine. Faxes work fine from "some" fax machines into a fax server, others (from one location, port network 5) hang and fail. Having the same network region, ip-codec. The only difference I can find in the two traces is:

fax:Relay modemff - the failed fax
fax:Relay modemT - the successful fax

Have tried T.38, pass-thru, and relay. This fax server records the fax and then sends it from there to recipient, and again, I have verified faxing works fine from fax machine PN5 to fax machine PN3 (where the fax server is). I don't understand why in the same network-region, ip-codec, one shows "off" and one shows "PT".

Thanks,
Shike

 

[Nick44]

Hi,
I have had exactly this problem, in two different sites.
At the first the problem was down to the modem on the fax server being old. Replaceing it fixed the issue. At the second site which used a Brooktrout TR114 fax board, we never got to the bottom of it, but we found a commanality in that the failed faxes all came from old machines. I did fax maintainance work many (many) years ago, and we eventually decided it was that the remote machines were trying to send in modified modified Huffman code, which upset the ip encapsulation of the codec.
The term modified is used twice deliberatly.

Speak softly and carry a big switch

 

[kpearlt3]

In your example the PT is referring to modem pass through. Can you show how you have the location 5 media processor boards and codec set configured when it connects to the main site that you are trying to fax to and from. I have found that fax pass through seems to work more reliably than fax relay. If you administer your ip-codec set for T.38 and the fax call has to go through 2 Avaya media processors Communication Manager will automatically use fax relay even though you have T.38 administered. If you can post those configs maybe we can see what's doing

 

[ShikePoke]

Thanks for the responses.

To kprfe: I tried pass-through, relay, t.38, all with the same result of "off" rather than "PT". It may indeed be either or both of Nick44's resolution, as it mainly is failing from one location.

Thanks, I've got the fax server vendor involved now, we'll see what his resolution is, and I'll post.

Ben

 

[Gibsonic]

i recall seeing some reference to t.38 PT in some firmware release notes for either clan's or ds1's or something recently. how up to date are you on your firmwares?

 

[ShikePoke]

Not very, they are on the latest 4.1 patch, but another vendor had been taking care of this network until recently. Could prove useful, thanks.