Voice Path Delay

[AdmanOK]

I have several remote sales offices that are connected to our CallManager cluster over internet VPN connections. Most of the time they work fine; other than the occasional voice breakup that is to be expected when running over a public network. One problem that seems to come up is a delay in establishing the voice path. This happens at one office on a very regular basis. The phone will ring and the user will pick up the receiver, however it takes about 10 – 15 seconds for the voice path to be established. They find themselves repeating “hello… hello?” into the handset about three or four times before the other person can hear them. The seems to be happening most frequently on external calls. The sites all have local PSTN connections coming into FXO ports on a local 2600 series gateway. This is used for both incoming and outgoing calls. I don’t see how where the latency is occurring as the voice traffic never actually traverses the WAN. The call control packets are obviously happening as the phone rings, and after that everything should be local so there should be no delay. Does anyone have any ideas?