how can I set a Cisco 2600 with BRI interface to send a BYE just after hangup?
Actually, if I hangup a call, nothing is done for exactly 30 seconds, and after them, a BYE is sent.
Can I set it to send BYE immediatly or after a couple of seconds?
Are you receiving Disconnect Q931 on ISDN with Progress Indicator. Check for PI=8 or PI=3
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.