Fax issue

yixiu0317 · ‎07-29-2012

Hi There,

I had problem to send fax to a particular number via our H323 gateway. The call was dropped after 15 seconds, when I call the number from normal IP phone, it took 20 seconds to hear the fax tones. Since we can not change the fax machine settings, is it possible to change some setting on the CUCM or gateway to fix the problem?

I checked the ISDN timer settings on the call manager and could not find anything useful.

Here is part of the isdn q931 debug.

Jul 27 09:49:14.185 AEST: ISDN Se0/0/1:15 Q931: RX <- CALL_PROC pd = 8 callref = 0x8595

Channel ID i = 0xA9839F

Exclusive, Channel 31

Jul 27 09:49:14.841 AEST: ISDN Se0/0/1:15 Q931: RX <- ALERTING pd = 8 callref = 0x8595

Progress Ind i = 0x8488 - In-band info or appropriate now available

Progress Ind i = 0x8482 - Destination address is non-ISDN

Jul 27 09:49:29.849 AEST: ISDN Se0/0/1:15 Q931: TX -> DISCONNECT pd = 8 callref = 0x0595

Cause i = 0x80A9 - Temporary failure

Jul 27 09:49:29.913 AEST: ISDN Se0/0/1:15 Q931: RX <- RELEASE pd = 8 callref = 0x8595

Jul 27 09:49:29.913 AEST: ISDN Se0/0/1:15 Q931: TX -> RELEASE_COMP pd = 8 callref = 0x0595

Jul 27 09:49:14.185 AEST: ISDN Se0/0/1:15 Q931: RX <- CALL_PROC pd = 8 callref = 0x8595
Channel ID i = 0xA9839F
Exclusive, Channel 31
Jul 27 09:49:14.841 AEST: ISDN Se0/0/1:15 Q931: RX <- ALERTING pd = 8 callref = 0x8595
Progress Ind i = 0x8488 - In-band info or appropriate now available
Progress Ind i = 0x8482 - Destination address is non-ISDN
Jul 27 09:49:29.849 AEST: ISDN Se0/0/1:15 Q931: TX -> DISCONNECT pd = 8 callref = 0x0595
Cause i = 0x80A9 - Temporary failure
Jul 27 09:49:29.913 AEST: ISDN Se0/0/1:15 Q931: RX <- RELEASE pd = 8 callref = 0x8595
Jul 27 09:49:29.913 AEST: ISDN Se0/0/1:15 Q931: TX -> RELEASE_COMP pd = 8 callref = 0x0595

paolo bevilacqua · ‎07-30-2012

Check that possibly is your calling fax that disconnects after 15 seconds, so you have to work on it, not on the CUCM.

yixiu0317 · ‎07-30-2012

Thank you for your reply, we just found another 2 numbers had the same problem, when I call from normal phone, it is ok, it is like "fax server-- CUCM -- voice gateway -- PSTN -- fax machine", from the fax server, I ran the wireshark debug and can see that the CUCM sent the relesae to the fax server, and did not see any release from the fax machine.

If my understanding is correct, T301 in CUCM is the timer manage the timeout for this, and it is set as 180 seconds, which make me confused

paolo bevilacqua · ‎07-31-2012

Can you take the same trace again, but only adding "debug vpm signal" ?

That will show if calling fax goes back to on-hook prematurely, as I suspect.