timer on sip phone

[mehrdad]

in a cos i change enable call duration limit on external calls to yes
and enable call duration limit on internal calls to no

in mitel phone it is work correct
its mean that in external call timer in enable but it is no action on internal calls
but we have some sip phone (atcom and yealink) and the timer block the internal calls on these sets

it is seem that all call duration of sip phone are external for mitel and can not detect of defrence of sip user and sip trunk

i hope it has a way to solve it

[x-man]

Try in the SIP device capabilities form.

[mehrdad]

i tried SIP device capabilities form but NOT solve it.
any idea? 

[x-man]

I suspect if it cannot be done in the phone settings then it can't be done; If I understand it correctley once the call is set up all the control is done by the SIP NOT the Mitel (RTP between end points). I have a site where the SIP phones will not delay ring because of the same problem.