i have just at the 8961 phones the behaviour:
If i enter i number (internal or external) at the Phone and press the dial button, the phone wait ca.4 seconds till the dial start.
So i changed the T.302 Timer in Service Parameters and in SIP Profile the T.302 Timer, nothing changed.
I don't have an idea for this Parameter in UCM 8.6.2, where i must change some things. Any ideas?
Is it 4 seconds before you start to hear ringback? If so the destination has to send a 180/183 before the phone will start playing ringback indicating the call is ringing on the far end. If it is not a delay to hear ringback, how do you determine that the dial has started from the phone?
Do you have any SIP dial rules applied to the 8961 phone under the phone configuration page in CUCM? That could make the phone wait before sending the dial string. You shouldn't have a delay within CUCM because there are no potential matches since you already tested changing the T302 timer (inter digit timeout) and that did not make a difference.
Those who have upgraded and that has fixed the issue likely were running into the slow user interface bug,