With the glorious assistance of this board I was able to locate the intercom button on a DKT 3010.

Now I am attempting to set this phone to forward all non answer/busy calls to voicemail @ 850. I am using the codes from here:
https://www.craigcommunications.net/pdf/dkt-3000-2000-user-manual.pdf

If I attempt to use Ext + #6041 the system reacts to #604 before I can hit 1 and asks for a destination. If I put 850 in then and hit #, it does nothing. Is there a secret manual I need to be using with the real codes? :confused: