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Disconnec tone after remote user hangup phone.

Hello Everybody!


I have this topology: SIP PBX <-> Cisco Voice Gateway <-> PRI ISDN


My problem is: When we make outside call and remote user hang up the phone, Cisco Vocie Gateway generate Busy/Disconnect signal for 30sec and only after that send BYE message. 


Can I disable this "Busy/Disconnect" signal and 30sec timeout before BYE? 

"Sh run" here:


isdn switch-type primary-net5
voice call send-alert
voice service voip 
 allow-connections h323 to h323
 allow-connections h323 to sip
 allow-connections sip to h323
 allow-connections sip to sip
 fax protocol t38 ls-redundancy 0 hs-redundancy 0 fallback pass-through g711alaw
  call start slow
 modem passthrough nse codec g711ulaw redundancy maximum-sessions 5
  bind control source-interface Loopback0
  bind media source-interface Loopback0
  subscription maximum accept 60
  subscription maximum originate 60
  redirect contact order best-match

voice class h323 1
  h225 timeout tcp establish 2
  call start slow



interface Serial0/0/1:15
 no ip address
 encapsulation hdlc
 isdn switch-type primary-net5
 isdn overlap-receiving T302 5000
 isdn incoming-voice voice
 isdn sending-complete
 no cdp enable


voice-port 0/0/0:15
 cptone RU
 timeouts interdigit 5
 bearer-cap Speech


dial-peer voice 1 pots
 tone ringback alert-no-PI
 description To PSTN
 destination-pattern 9.T
 port 0/0/0:15

dial-peer voice 9995 voip
 destination-pattern 244....
 redirect ip2ip
 no modem passthrough
 session protocol sipv2
 session target sip-server
 dtmf-relay rtp-nte
 codec g711ulaw
 no vad



 nat symmetric role passive
 nat symmetric check-media-src
 max-forwards 12
 retry invite 3
 retry register 3
 timers register 150
 sip-server ipv4:



Everyone's tags (1)
Community Member

A part of logs: disconnect on

A part of logs: disconnect on ISDN and Disconnect on SIP:

Jul  9 18:20:07.962 KZT: //7290882/2DF8F69BB294/SIP/Info/ccsip_indicate_rt_packet_stats: Processing stats for callid=7290882, proc_id=9
Jul  9 18:20:15.266 KZT: //7290882/2DF8F69BB294/SIP/Info/ccsip_indicate_rt_packet_stats: Processing stats for callid=7290882, proc_id=9
>Jul  9 18:20:16.326 KZT: %ISDN-6-DISCONNECT: Interface Serial0/0/0:4  disconnected from 87021231234 , call lasted 10 seconds
Jul  9 18:20:22.690 KZT: //7290882/2DF8F69BB294/SIP/Info/ccsip_indicate_rt_packet_stats: Processing stats for callid=7290882, proc_id=9
Jul  9 18:20:28.050 KZT: //7290882/2DF8F69BB294/SIP/Info/ccsip_indicate_rt_packet_stats: Processing stats for callid=7290882, proc_id=9
Jul  9 18:20:39.410 KZT: //7290882/2DF8F69BB294/SIP/Info/ccsip_indicate_rt_packet_stats: Processing stats for callid=7290882, proc_id=9
Jul  9 18:20:45.770 KZT: //7290882/2DF8F69BB294/SIP/Info/ccsip_indicate_rt_packet_stats: Processing stats for callid=7290882, proc_id=9
Jul  9 18:20:46.326 KZT: //7290882/2DF8F69BB294/SIP/Media/sipSPIUpdateRtpSession: stun is disabled for stream:4AB84068
Jul  9 18:20:46.326 KZT: //7290882/2DF8F69BB294/SIP/Info/ccsip_call_statistics: Requesting stats for callid=7290882
>Jul  9 18:20:46.330 KZT: //-1/xxxxxxxxxxxx/SIP/Event/sipSPIEventInfo: Queued event from SIP SPI : SIPSPI_EV_CC_CALL_DISCONNECT


Hi 1- try  the below:-voice



1- try  the below:-

voice service voip

ip address trusted all

no ip address authenticate 


2- Try to do catch debug ccisp messages 



please rate all useful information

Community Member

I've received this solution

I've received working solution there:

IOS will not send BYE immediately if PI is received which indicates IOS needs to listen to inband tones being sent by the telco. Audio cut through would be one way once the Disconnect is received. i.e. from Gateway to IP Phone. In such a case PSTN controls releasing the call. Telco would send a RELEASE message after 30 seconds which would result in call tear down and IOS will send BYE to SIP leg. 

You can try the following workaround: 

Configure following in global config mode: 

voice call disc-pi-off 

Remember above is only true if Q931 Disconnect comes with a PI. 

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