Charles, I've had
this intercom at the front entrance of my house for 10 years now.
I have the video (with night vision) and intercom system. Basically what happens is when someone rings the intercom at the front door, my phone rings three times consecutively (distinctly different from a regular phone ring). At that time, I can answer the phone and talk to them at the front door, and I can also change it to a specific channel to view the camera outside.
You can also link your cell phone to this device; I do this when I go away. My cell phone is programmed into the system, so when I am leaving the house I just have to punch in a three digit passcode on my home phone, thus transferring the intercom calls to my cell phone.
The system is very versatile and works extremely well.
If you have any questions, ask away.
