Hi,

thx for ur respond, I don't use the same dial-peers for anlog lines and E1-R2, and when i call over E1-R2, i hear smost of times normal ring back tone( normal call back tone) and some times i hear fax ring back tone, i don't know why !!!

can u plz help me it's really urgent, thx in advance.

OK, just to clarify, when you dial the same fax number on the E1 R2 circuit that you dial on your analog circuit, you *sometimes* hear ring back and sometimes you do not. Other times you may get ring back and then fax tones as well? If you dialed the same fax number on your E1 R2 circuit 10 times, you are telling me that you get different results in regards to hearing ring back and fax tones?

Also, what device is terminating these fax calls? Is it another Cisco voice gateway or a fax server or some other device?

Regards,

David

Hi David,

Thank very much for ur interrest,

In fact, i can confirm u these things:

1- Yes, when i call the Fax number (fo exemple 71 261 401) on the E1 R2, for ten times, most of times i hear normal ring back tone, and then i can see on my IP phone: connected, and i don't hear fax ringtone.

2- Yes,when i call the Fax number(for exemple 71 261 402) on the PSTN , everything goes fine, and i hear fax ringback tone (modem tone).

3- the device that is terminating fax calls is a Fax Server

Thank you for ur help in advance. it's really urgent.

It sounds like you may be having an audio cut through issue over the E1 R2 link or something else is going on. Let's gather some more information and confirm that audio is at least occurring correctly on the IP link between the fax server and your gateway. Can you provide the following information so that we can see what is happening on the IP side of the connection?

- a packet capture of the analog call where you hear the fax tones

- a packet capture of the E1 R2 call where you do not hear fax tones

- a sh ver and sh run from your voice gateway

These captures will let us confirm if the G.711 audio is working bidirectionally and if it contains fax tones. If so, then we know that this audio is getting blocked at the gateway or some where else. If the G.711 is not set up correctly or no audio is present within the G.711 then we need to troubleshoot further between the gateway and the fax server. Capturing a working analog call will provide us a useful comparison to the failed E1 R2 call.

Regards,

David

Hi David,

Thank u for u assistance, i really appreciate that.

In fact i can't make a packet capture like u said because i'm in distant site.

But here it is joined the show run and show ver.

In fact i have a question :

Does the fax work over an E1 R2 ?? maybe it could be a problem of E1 R2 ?? but what makes me not sure of it, is that sometimes it works over the E1 R2 and i can hear fax tone, but only sometimes!!

i made a test here in my office, with another 1760 but over a PRI and it worked without any problem!

i'm preparing to make a "debug h225 asn1" on the 1760 gateway as soon as possible (the problem that it's on production and there is calls on it) i'm planning to make a debug @ night, where no calls on the gateway and i make my fax call and see what the debug is going to tell!

An other remarqu : is when i make a test call on the fax number over the E1 R2, and i make "sh voice call status" i see that the codech is g711ulaw, so it didn"t change to t.38, so is there commands to debug the fax signalling or codec ??

Thanks a lot David.

I went ahead and did some quick bug searches. You may be right about E1 R2 on the Cisco voice gateway being the problem for your fax calls but it is difficult to confirm without detailed debugging and packet captures. The bug id I found was CSCsf08786 titled "E1 R2 signaling causes T38 faxing to fail with XMedius T38 server". I am not sure what brand of fax server you have but I did not get the impression while reading about this defect that it only pertained to a certain fax server brand.

You can read the release notes for this issue by entering this defect ID into the Cisco Bug ToolKit at http://tools.cisco.com/Support/BugToolKit/action.do?hdnAction=searchBugs

if you still need additional assistance with troubleshooting this problem or learning more about this defect, then you will probably need to contact Cisco TAC as this problem is moving beyond what can be addressed via a forum environment. I hope that this information is helpful.

Regards,

David

Hi David,

Really thanks for your help.I appreciate that very much.

I've done a h245 debug on the gateway,while i have a call with fax ringback tone and when i don't hear fax ringback tone.

The files are joined.

Just to make eomethnig clear (it's my fault): In fact in my tests sometimes i hear fax (modem) ring back tones and sometimes i don't hear anything (but in my IP PHone i see : "ringout" then "Connected" so i called this normal ringback tone!) So in real when i maje tests i "sometimes" hear fax (modem) ringback tone and in some other tests i just don"t hear anything (but in my IP phone i see ringout then connected)

Also, i work with HYLAFAX as Fax server.

i did the test over an E1 PRI in my offcie with a similar platform (cisco 1760) and it worked great. But still have th same problem with the E1 R2!

Hi, David, i still have problems with my Gateway, but it seems that i begin to solve the random behavior of the Gateway.

Here is what is new:

In fact when i was troubleshooting the gateway and through the multiples Debug i was doing and call tests... i found a very strange thing : when i activate the "debug h245 asn1" on the Gateway all my fax calls are successful and when i desactivate it no fax calls are sucessfull!!!

i made those test many times.i made 60 calls without "debug h245 asn1" all 59 calls where not seuccessful.

I made then 60 calls with "debug h245 asn1" activated on my 1760 Gtaeway and all the 60 calls where successfull!!!!

It's really unbelivable!!

Can the problem with the H245 stack of my Gateway? is this possible ?? and if it is, is there a way to remedy to my problem??

Plz i need urgent help!!

Thanks in advance

Hi, David, i still have problems with my Gateway, but it seems that i begin to solve the random behavior of the Gateway.

Here is what is new:

In fact when i was troubleshooting the gateway and through the multiples Debug i was doing and call tests... i found a very strange thing : when i activate the "debug h245 asn1" on the Gateway all my fax calls are successful and when i desactivate it no fax calls are sucessfull!!!

i made those test many times.i made 60 calls without "debug h245 asn1" all 59 calls where not useccessfull.

I made then 60 calls with "debug h245 asn1" activated on my 1760 Gtaeway and all the 60 calls where successfull!!!!

It's really unbelivable!!

Can the problem with the H245 stack of my Gateway? is this possible ?? and if it is, is there a way to remedy to my problem??

Plz i need urgent help!!

Thanks in advance

Good troubleshooting!

If fax calls work when "debug h245 asn1" is enabled and fail when the debug is disabled, then this is a software defect in the voice gateway. This sort of problem has been seen before. For example, the defect CSCef85823 exhibits these same symptoms but this defect should be fixed in your IOS version (12.4(18a) according to the sh ver that you posted).

These types of defects usually have to do with timing discrepancies in IOS processes and enabling lengthy debugs can resolve these types of issues on rare occasions. In your situation, you may want to try and load the latest 12.4T image to see if this problem has been fixed. if not, then you are going to need to contact Cisco TAC to troubleshoot this further. They may be aware of an existing defect for this problem or they will need to open a new defect for this issue.

Regards,

David