This took me a while to figure out, and there is nothing on the forums or anywhere else for someone to look it up. You try everything you can think of to provision this DECT Cordless device, and it's not supported by 3CX, so you won't get much help. Grandstream wasn't much help either. I was told the device had to be on the same LAN with the server. Either bridge another 3cx install, or install a VPN. For those new to 3cx, like myself, go to the dashboard of your 3CX install. Look at the event log. You'll see a message there that it's being blocked. A message like SIP request (REGISTER) from (IP Address) was rejected. Reason: Block WAN requests is ON. Go to the extension that you are trying to register, and click on the options tab. Uncheck the box that says Disallow use of extension outside the LAN (Remote extensions using Direct SIP or STUN will be blocked). Reboot the phone, and as long as you have the credentials right, the phone will register.
Another thing, if you have more than one cordless to set up on the base......log into the phones interface, under DECT, click on sip account settings and enter the credentials for the extension for that cordless unit. Set the HS mode to the handheld number....HS1..HS2..etc. Now, go to DECT, and click on Handset Line Settings. Change the HS number to the extension you are trying to register under the proper account.
It should be the same for the DP715/710.
Another thing, if you have more than one cordless to set up on the base......log into the phones interface, under DECT, click on sip account settings and enter the credentials for the extension for that cordless unit. Set the HS mode to the handheld number....HS1..HS2..etc. Now, go to DECT, and click on Handset Line Settings. Change the HS number to the extension you are trying to register under the proper account.
It should be the same for the DP715/710.
