We have an Inter-Tel 5000 v2.4 system with a mix of Mitel 5330 and 5224 IP phones. I setup my extension to ring to an alternate extension (as well as any calls to my DID number) which works just fine. We have a 20Mbit synchronous connection at the location of the main system and bandwidth is definitely not an issue here, I've triple checked. At home I have a 50Mbit down/5Mbit up connection and I've also confirmed that bandwidth is not a problem at home either.
Unfortunately the phone doesn't work as expected some of the time...symptoms include picking up the phone but not getting a dial-tone right away, or hanging up and the call not being dropped immediately. If I talk to someone from home, it may take 5-10 seconds for the call to end on my end. Sometimes the phone will simply lock up and display the blinking block cursor on the phone's display.
I've ruled out any interference from other running applications by only plugging the phone at home into my router (Buffalo router running the latest DD-WRT firmware). I even enabled QoS on the router and gave the phone 1.5Mbits (way more than enough bandwidth) based on its MAC address, but that didn't resolve the issue either.
We use a VLAN for the phones on our company network, but I'm not on the home network. That and the fact that I'm connecting to the external IP of the 5000 unit instead of the internal IP is the only difference in setup.
Am I missing something here? Is there a setting I've overlooked that's causing me this headache?
Thanks in advance!