I am having an issue activating/registering this phone with the free 3CX pbx. The front of the phone shows 7961, the back of the phone shows cp-7961g. Between google and the walkthrough for this phone on the 3CX site, I thought I would be able to get it configured, but no luck. Can anyone help? I don't think the phone has any firmware on it (no SCCP or SIP) and I am wondering if that might be a problem or the problem. Here is some information- I can get the phone to boot up and connect to a TFTP server and I can see packets in wireshark that it made a connection to the TFTP server. I followed this guide- http://www.3cx.com/sip-phones/cisco-7940g-7960g/ and it doesn't say anything about CTL, SEP, or XML files, the TFTP program stated that it was looking for those 3 files. The download from the 3CX site didn't contain those 3 files. I googled and found some default CTL, SEP, and XML files and I created them in notepad++, this time TFTP showed that it grabbed the additional files it was looking for, but the phone says, configuring IP....updating CTL.....then CTL Update failed (it didn't do that before I added my 3 custom files), so it must be making progress, but still isn't registering. The 3CX web gui/portal is not very responsive on my windows 10 laptop, not sure if it needs a reboot or if the laptop isn't powerful enough, this is just a test/experiment, so it shouldn't be an issue, but I do have another windows computer I can install this on if I determine that my laptop is the reason that it is running slow. My questions are: 1- this phone is compatible with 3CX, so I must be doing something wrong, can someone confirm? 2- does it matter what the existing phone firmware is and at which level? I bought it used, it could be that it wasn't wiped properly and that I only have a partial config on here? 3- Do I need to create my own CTL, SEP, and XML files or should those already be on the phone? Thanks in advance for any input/help.