There was another post regarding door phones with a camera in it. Normally these units have some sort of an interface box that connects up to your TV monitor with a composite video output connector (RCA). The problem with this is, if you are watching another source (like cable), when the doorbell rings, you have to switch your TV source to another input to see the camera.

I was told there was a unit available with a "loop through" capable of allowing your existing source to be watched and the camera would automatically inject the signal when the door bell rang (or a motion detector triggered). I would think it can only work with external sources so you would have to have a digital cable box or satellite receiver.

Has anyone seen something like this? I tried googling, but I'm not sure what to call it.

I have been looking for something like this myself for a while...but no luck, if anyone knows of something I would love to see it. The best I have been able to do Is set the camera up on an Input and let the enduser hit the picture in picture button.

I looked in a couple catalogs and didn't see anything to do that only call-id when phone rings.

You could connect a video switcher that has split screen and remote contacts so when bell rings tv would go to split screen with camera and video signal both showing.

that could work, any product suggestions?

Yep, good idea metalcom, I sort of have that now. Years ago, Zenith made an RF A/B switch that was run by an AC wallwart adapter. It was made for the Jerold cable box/pay TV descrambler times. The idea was you plug the 12V adapter into the cable box switched receptacle and the switch, which was normally at "A" would go to "B" (the cable box) when you turned on the pay TV rig. I have a Speco front door camera with a chime interface box, so I tapped the 12V to run the A/B switch from the interface. I also am running a channel 3 modulator on the camera as well.

Now that HDTV digital cable boxes, satellite, and DVD is popular, most of us don't use the RF input on the TV, or even the composite video for that matter. Most home theatre receivers will also do the video switching and some with up conversion that will do component. It would be nice to have a camera interface that can wire between the receiver and the TV with component or at least S-video.

I have been getting asked for this now by customers as well as my own place. The split screen idea is good, I wonder if anyone makes a split screen unit that would take different input type sources (like component, S-video, or composite), probably wishful thinking!

You could try MCM https://www.mcminone.com/Default.asp?cookie%5Ftest=1 they have a lot of home and security video equipment
Get the catalogs theres a lot more then on the web site, plus good monthly sales.

Also this product may work for some of you, https://www.iautomate.com/h441.html
The automatic switching will be the most difficult to find

thanks merritt I already buy from MCM I will take a look