A Haa... found this on another forum :
There is no great way to determine which device is "most compatible" with IP Office. Although I have used the Viking product, I'm sure there are many others that will work equally well. It is really just emulating an analog station. When the doorphone button is pressed, the device goes off-hook. The rest is up to the phone system. The particular model that I have used is Viking's (
model E-10.
1. Connect to analog station port.
2. Using the Manager administration application, navigate to the user section and select the analog station to which the device is connected.
3. On the shortcode tab, create a new shortcode as follows:
Short Code= ?D
Telephone number = Destination where you'd like doorphone to ring, i.e. extension or hunt group
Line Group ID = 0 (unless you're having doorphone ring off site, at which point you'd enter a valid line group ID)
Feature = Dial
AND ALSO
try these sites
If you go for Bpt you will need analogue trunk card and set the line for the door entry to incoming only, change the line group id, then point that id to door hunt group in incoming call route.
This has now "given me some pointers