[fraggle]

I have the above phone. I set the oublund rule up in 3cx to that you dial # to use voip.

When I dial # the phone ends the call immediately

[amygoda]

Because of dial plan
use numbers better

[nmartin]

As amygoda sys, it's to do with the phone's configured dial plan. Download the phone Administrator's Guide at http://www.LinkSys.com and look at the section:

LinkSys IP Phone Field Reference -> Ext Tab -> Dial Plan

and you will see a description of how the phone matches the dialled number against its 'acceptable' number format (a bit like a regular expression match statement).

By playing around with the expression you may be able to craft a dial plan to match your requirement. See http://en.wikipedia.org/wiki/VoIP_Dial_Plan for more information.