Statistically, no. I bet they are used in less than 1% of cameras.
That said, there is a bunch of neat things one can do with them - Inputs/Outputs Tutorial
I used an input once on a PTZ, set it to go to a preset when a sensor triggered. One would wish that you could pay less for camera models without all the extra external stuff. I wonder what kind of a price cut you could get if you stripped off SD card storage and I/O. Seems like on a lot of cameras (ie Axis) that comes standard and isn't used 95% of the time or more.
Chesapeake & Midlantic
Back in Ye Olden Dayes (TM), we used to use them all the time. Connect the VCR's alarm I/O to a PIR in corridor mode, or to a magnetic contact on a door, set it to a higher than normal frame rate, and the VCR would record on motion only. Useful not only for saving tape space, but also made it easier to search for incidents of motion.
The "record everything and let the analytics sort it out" attitude only arose a few years after the mass adoption of DVRs, because even the smallest hard drive could hold way more stuff than the longest VHS tape. So, slowly but surely, manufacturers started to allow higher resolutions, higher frame rates, and so on.
But, as John says, there are all sorts of neat stuff you can do with I/O ports, and it's pretty cheap to add it to the camera, so why not? In fact, I know of integrators using PIRs to create verified motion bookmarks, proving that what goes around, comes around.
I can't think of a single time I've done I/O at the camera (my coworkers may have a example), but I do use I/O via external ethernet edge devices quite often. I do appreciate the manufacturers that are putting them there should the need ever arise. You can do a lot with them built right into the camera but it's long been more of a selling point that rarely, if ever, gets implemented in the field. The most commonly cited example is:
"You can hook a motion detector into the PTZ and have it pan over to a location when the motion detector is tripped."
Replace motion detector with whatever contact closure input you want (nurse call, intercom, duress button, etc) and I have heard every variation of the above statement since I entered the industry. I have not once seen anyone actually make the connection at the camera. That's not to say it doesn't happen as other people in this thread seem to have used them.
I get quite a few applications that use the I/O. Not every day, but it is common. I also use the I/O on a camera to start/stop recording on the edge or NVR for interview room.
Some manufacturers do have models that are lower cost and do not include SD card, I/O, etc.
Take for example the Panasonic WV-SP105 vs. WV-SP305 (just to name 1). Yes, there are some other differences (interchangeable lens vs built in), but the concept is to remove non-core hardware features to save $$.
Samsung also does this. Take for example the SNV-6013 compact vandal dome. Great price point, all the same WiseNetIII features, but no I/O, no audio. That one does have an SD card slot.
Samsung also has a LiteNet series that strips certain features while having 1.3/2/3 megapixel resolution for low cost.
For everyday cameras in stairwells, hallways, etc., these can really help keep costs down, or allow your money to go farther and deploy additional cameras due to the savings.
IPVMU Certified | 01/23/15 02:29am
We very rarely use the I/O onboard cameras. I doubt we hit John's 1%. That said, we do associate input events with camera/video actions and trigger outputs extensively. Those inputs and outputs reside on access control panels. We do quite a bit with outputs onboard SIP intercoms, too.
We focus on complex enterprise systems. If we sold and installed smaller systems, especially those without access control panels, I believe we would use camera I/O quite a bit.
We use them quite regulary. For several purposes.
One being intercom. If a camera is in the neighbourhood of a intercom, we make a contact to the camera to move it to a PTZ position and alarm the VMS.
Others being gates, for the same purposes.
And there are also situations where we use them with encoders to create snapshots of installations and them save them to the SD card so can analyze the images later.
And another thing we do is connect them to our security system to trigger them to PTZ positions and report to the VMS once we see our AIR being triggered.
There is an interesting updates which unfortunately no one has commented on HERE ... I believe that we integrators must begin to add more value/customization. Back only 2 years ago, we could make money selling cameras at a hefty premium. Now with 3 MP cameras under $100 surpassing the picture quality and robustness of cameras 5 times the price, our survival depends on the value we add to the systems we install and design.
Typed this then realized it was in the tutorial linked above, but I actually incorporate them with access control as a soft trigger to open a door.
Mainly in the scenario where you have a receptionist around the corner from a locked main door. I use the input with a Home Depot purchased doorbell. Using event linking, I set that input to create an alarm in the VMS and either notify through email, pop-up the camera, or sound clip (havent done the last, but just realized I can). From there I link the camera output to an input on my card access system that is programmed to unlock the door when triggered. In the VMS, I set up a soft trigger button on the screen so the receptionist can view, and let in whoever is at the door without leaving the VMS or me having to hardwire a button to his/her desk. Haven't used the full duplex audio to create a complete intercom system, but I suppose I could.
My access control is decentralized so it makes completing the above extremely easy. Instead of having to cable the inputs/outputs back to the server room, my cable run may only be 5 feet away from camera to access control device.
The small businesses really like this because it's pretty inexpensive, simple, and helps alleviate the need for a dedicated front entry receptionist.