This is probably because only the voice vlan points to DHCP scope with option 150 defined. ATAs jut like phones can work on any vlan as long as they can pull the config from TFTP via option 150 (if using DHCP) and communicate with the CUCM call processing servers.
I am not sure I fully understand you. Normal IP phones will send their DHCP request to the voice VLAN, get the option 150 info, download their config and then register. There is no need for the access VLAN on the switch port to have option 150 set.
What I am seeing with the ATA187's is that they send a DHCP request on the access VLAN, get an IP address but no option 150 information and then just stay in that VLAN.
I can get them to register by changing the access VLAN on the switch to be the same as the voice VLAN but I want to avoid this unless it is the only option as it makes the ports unusable for standard phone and PC connections.
I'm not able to access my old voice mail messages all of a sudden. The recording says something like 'the message is currently not available'. This has never happened before in all the years I have been using this system. I have t...