3CX v12.0.35528.640 SP.5 Cisco SPA514g phones with FW 7.5.5 We have about 30 users in our office, and about 7 or so need an extra extension on their phones. I manually edited the settings on these phones web interfaces. The problem I've been having is that every morning when I come in, the line keys have all reset to 1. I found this topic (http://www.3cx.com/forums/cisco-spa504g-will-not-provision-line-key-29152.html) about provisioning different line keys. That looks like what I want to do to get the separate extension to work permanently. My question is, is it possible to use this on just a few phones?