On peut bien sur disabler l'indicateur des missed calls: "missed calls indicator disabled"
Sinon, plus utile, avec la une 1.6, et l'option c de dial , et depuis la 2.4 , il y a ca:

Code:
Reason Header Field in SIP Message
The IP Phones now support the receiving of the Reason Header Field in a SIP CANCEL message, 
as described in RFC3326. This allows a call that is answered from somewhere else to still display 
that it was answered elsewhere in the Callers List. Also, the missed calls indicator and counter do 
not change.
Pas testé, je travaille encore souvent sur base 1.4...

Sinon il y a aussi "callers list disabled" , pour ne pas stocker l'info.

Cheers !
Fastm3.