I have several IP phone connected to my Nortel BCM400. A handful of the phones have the following problem:
-When trying to answer calls, picking up the handset does not always answer the phone. Answering on speaker works more frequently.
-When trying to make calls, same type of issue. Picking up the handset you can not always get a dial tone right away.
It feels like the phones have a delay trying to connect to the phone system. Though they do ring just as fast as digital phones when calling them.
I have HP4108gl switches, everything is on the one vlan (not best practice i know) there is a fibre link between switches. one switch has the phone system connection, and the ip phones are on the other switches. Not all phones are effected it appears.
I suspect it is networking related but not sure where to look first.