The configuration files in the download section do work, I tested them extensively...
The Cisco 7940 is obsolete and there hasn't been any new firmware updates released in years, so no reason why the config files wouldn't work now. Unfortunately there is no one install fits all scenario, and so some minor configuration changes will need to be applied depending on what VoIP provider you're using and your local network configuration. Any reason why you want to use the Cisco 7940 series IP phones? These are not native sip phones and have been obsolete for years now. If you like the Cisco brand then I recommend that you consider the SPA series phones. The SPA series are SIP based VoIP phones with a web GUI built in! You configure them in the same way you would your WiFI router, see a working demo here
Anyway, first things first. You need to get your TFTP server up and running first! No point messing around with configuration files if the phone isn't even capable of pulling them from the server. Are you sure that the phones are not being blocked by a firewall and that the phones are on the same network as the phones? Factory reset the phones and start again from scratch!
It's pretty straight forward:
- Press Settings and Option #9 Unlock Config. It will ask you for your password. The default would be ‘cisco’. Then go to Option# 3 Network Configuration -> Option 32 Alternate TFTP and change this to ‘YES‘
- Then go to Option #7: TFTP Server and change this to the IP Address of your TFTP Server and press ‘Validate‘ and ‘Save’
Providing your TFTP server is up and running and your firewall preventing access the phones will pull the configuration files automatically. What exactly does it say in the TFTP servers log files?