Analog Fax Line Problem

[bassphone]

I am having a problem with a fax line that I cannot figure out. Here are the details.

System A & B are both 3300 ICPs running on 6.0, the systems networked VIA IP trunks. System A has 3 PRI trunks that the DID numbers come in on. The fax machine with the problem is in System B on an ONS card in a per node.

When the Fax number in system B is dialed from a fax number in system A the fax is transmitted without a problem, however when the fax number is dialed from an outside number it fails intermittently.

I tested dialing from System A to B direct and using an outside line. When calling using an outside line, I hear the fax machine in system B answer and fax machine in system A transmit. I did notice that the normal fax data noise was distorted sounding on the outside line when the transmission failed. I had someone send a fax to the line in system A from outside the fax transmitted without a problem.

I ran a SMDR report in system A to find out the incoming trunk used for each call. Both calls (the failed call to system B and the successful call to system A) used the same trunk in system A.

There are other Fax lines in system B that experience the same problem.

The Question is how to isolate this problem?

 

[619Tech]

How is your IP trunking connecting (VPN, MPLS, other...) the two controllers? Is there a possibility of some compression happening between them? T.38 configured/supported by MPLS carrier (if any)?

 

[Lundah]

Is compression enabled on the route connecting A to B?

 

[kwbMitel]

Compression? T38?

**********************************************
What's most important is that you realise ... There is no spoon.

 

[bassphone]

The trunking is IP/xnet
Where am I looking for the compression settings?
Also the PRI is connected via a NSU not an on board T-1.

 

[bassphone]

There are No Fax over IP t.38 Licenses in either system

 

[kwbMitel]

Without T38, Fax over IP is a crap shoot.

do you have faxes on system A working OK?

I've had some success with using IP-Analog converters where in your case the converter would be at site B but registered to site A

**********************************************
What's most important is that you realise ... There is no spoon.

 

[bassphone]

kwbMitel, faxes in ststem A work

 

[kwbMitel]

With Faxes on system A working I will bet that the issue is with how Mitel handles the audio stream over IP between the systems.

Mitel's solution to that problem is to install T38 licensing and hardware to guarantee the bandwidth that faxes require.

You may already have built in hardware that will support T38 but you may not (depends on the age/chassis type/ and especially the DSP modules)

Cheapest/quickest one-off solution is to go with an analog/Sip converter registered to controller A on site B

Most recently I've been playing with the SPA112 from Cisco - simple to implement and relatively cheap considering it's Cisco. <$50 US

**********************************************
What's most important is that you realise ... There is no spoon.

 

[Lundah]

What kind of bandwidth do you have between the controllers? If they're on the same LAN, you may be able to just turn off compression (in Route Assignment, set "Compression" to "No") and get away with it, I've seen it work. If you're traversing a WAN link, that may not work and then you'll have to go T.38.