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UC 500 no Ringback

I need help with this scenario:

1- C1861-UC-2BRI-K9 (c1861-spservicesk9-mz.124-11.XW6)


1- ISDN Line

4- Cisco IP Phone 7940 (P00308000500)


User calling -> ISDN Line -> VIC2-2BRI-NT/TE -> CME 4.2(0) -> Phone 7940

When outside user calls, the 7940 rings and no RING BACK or any sound to the calling user

is provided. No RINGBACK or sound in the line to the calling user.

When the user is busy the line provide the busy ring.


*May 12 02:15:43.308: ISDN BR2/0 Q931: RX <- SETUP pd = 8 callref = 0x01

Sending Complete

Bearer Capability i = 0x8090A3

Standard = CCITT

Transfer Capability = Speech

Transfer Mode = Circuit

Transfer Rate = 64 kbit/s

Channel ID i = 0x8A

Exclusive, B2

Called Party Number i = 0xA1, 'REMOVED'

Plan:ISDN, Type:National

*May 12 02:15:43.356: ISDN BR2/0 Q931: TX -> CALL_PROC pd = 8 callref = 0x81

Channel ID i = 0x8A

Exclusive, B2

*May 12 02:15:43.380: ISDN BR2/0 Q931: TX -> ALERTING pd = 8 callref = 0x81

Progress Ind i = 0x8188 - In-band info or appropriate now available

NO RINGBACK -------------------------

*May 12 02:15:48.035: ISDN BR2/0 Q931: RX <- RELEASE pd = 8 callref = 0x01

Cause i = 0x829F - Normal, unspecified

*May 12 02:15:48.043: ISDN BR2/0 Q931: TX -> RELEASE_COMP pd = 8 callref = 0x81



Re: UC 500 no Ringback

Take a look to the following link, it also applies for the UC-500

I recommend you to start with the progress indicator.


New Member

Re: UC 500 no Ringback

Good afternoon

Thank you for your answer.

We have already noticed this document and several settings that include the PI, and without results.

Further tests with delivery to a dial-peer VOIP establishing without delay the voice channel it's ok

On the voice channel opened you digit any extension and get the ring back.


What I find is that the Telco open immediately the voice channel without acknowledgment from the router to open the voice channel.

Tests to Telco it appears that not get the following output of the "debug ISDN standard"

* Mar 4 02:14:18.807: ISDN BR2 / 0 EVENTd: L3_GetUser_NLCB: Got NLCB 0x83AE6510 int_id 0 call_id 0xB in ESTABLISH_WAIT event is 0x87

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