Fax Relay or Fax Pass-Through

[chan-kuen.hui]

Dear All,

I have a 2651XM Router with 4 x FXS port and 1 x T1 port. T1 port is connected to PSTN and 4 x FXS port is connected to Fax machine and modem.

A CCM 4.0 using MGCP for call control on the 2651XM Router.

I have problem when send or recieve fax via PSTN. Miss pages always happened.

I have read some material on fax relay and fax pass-through.

How can I use these to solve the problem or Is there other method to prevnet this problem?

Thanks.

Regards,

CK

[rbradfield]

if the faxes are going out the local PSTN then Fax pass-thru is better, I found fromm experience that the analog gain being to high causes the majority of fax problems. When using Fax Relay this level cannot be controlled, but using Fax passthrough it does that is the "input gain" and "Output Attenuation" commands on the analog interface do control th level

[chan-kuen.hui]

Dear Sir,

I am using Ricoh Fax Machine.

Do you have any sample config about this?

Thanks.

Regards,

CK

[dgahm]

MGCP and faxing has problems when the call is between analog ports and T1s on the same router. This is a known issue, and the TAC told me that a fix would require such an exensive re-write of the IOS that it will not happen anytime soon.

In this same scenario I converted to H323 fax relay and faxes are working well. There is a document that says you also have to force the H323 call setup through the Call Manager by using bogus numbers and translations, but I did not find that to be the case.

Another problem is ECM/Super G3. Before you do anything make sure you have disabled ECM, which will also disable Super G3.Some fax machines have an option to disable Super G3 separately, if so disable both. Super G3 calls look like modem calls (V34) to the router, and will not be detected as fax calls.

Good Luck