Contractor Talk - Professional Construction and Remodeling Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
1,443 Posts
Discussion Starter · #1 ·
Obviously, I was snoozing under a shady tree when the subject of "virtual circuits" was being discussed during my physics or engineering class. I am hoping that some of you with much more knowledge and experience than I can explain it to me.

Here is the situation ( I can add a diagram later if needed): Client has a door bell. Bell has two wires from the transformer supplying 16vac to the circuit - one red, and, one white. One terminal (red wire) goes to the bell, the terminal (red also) goes to the door button. A white wire goes to the bell, and, is spliced to the white wire also going down to the button. So.....when you push the button, it completes the circuit (i.e. connects the red wire coming down to the white wire going up)to the bell annunciator, thus making the tone.

Here is the fun part.........A device replaces the door button and uses the wiring (red and white) to transmit video and data (ie: door bell cam) to another device that receives this info and transmits the video and data to a POE switch, thereby allowing the client to have video images on their network (at least from where the door button used to be).

But the issue is, the two wires going down to the button have to be disconnected from the 16vac transformer, and, be dedicated to those two "conversion" devices. So now the door bell doesn't work (cus half the circuit is missing).

So.....another device is added to the system that supposedly produces a "virtual circuit". It connects to the receiving device (the one that is up in the closet next to the 16vac transformer and receives the two wires coming up from the door button device - remember that one ;))

This virtual circuit supposedly integrates within the system and takes data from the door button on the camera and through the magic of the "virtual circuit" supplies power (40vDC) through the POE switch to the door bell annunicator.

This has all been explained to me by the guy who designed the system, bought the components, and, had me install it. This is one of my partner firms who basically goes out and sells stuff, that we end up installing. It has been ok for the first 2 or 3 years, but now he seems to have lost it mentally for the last year, taking on projects that are poorly planned and researched. Plus he seems to have learned nothing from the thousands of dollars of training on this stuff.

To me, if you have half a 16vac circuit on one side, and, half a 16vac circuit on the other, then you hare going to have to have a switch or relay connecting the two. Sending (however a method) 40vDC to a 16vac device is going to produce nothing. Having circuits connect virtually or in a cloud somewhere doesn't do squat.

But my "expert" partner on all this keeps telling me that I don't get it. It's all done through the magic of a virtual circuit.

I am hoping that someone on this forum with greater knowledge than myself can set me straight on this.
 

·
Contractor of the Month
Joined
·
26,075 Posts
What's the model number/brand?

The output of the attached device that you describe as a virtual circuit is either a dry contact output to the doorbell which you supply your own transformer or it is a 16vac triggered output for the door chime. I highly doubt it's a 48VDC output, but that's not outside the realm of possibility.

Virtual circuit is a cute way of putting it, but the device is most likely IP.
 

·
Registered
Joined
·
8,656 Posts
Thats easy, you're missing the Magic Wand? :laughing:

I used to install/repair apt. intercom/bell buzzer systems and I agree with you "virtual smirtual" you still need to interconnect the 2 systems and something to separate the different housing units ( 2B, 2A etc). In addition to opening the door with electric strike or electronic knob, it seems like something is missing.

Unless it is a completely addressable system using a building wide LAN.
 

·
Registered
Joined
·
1,443 Posts
Discussion Starter · #4 ·
Hey guys, I am going to follow up on this. Free time just came to an end and we are booked for the rest of the week, through the week end. I will come back with diagrams and particulars.

The camera system is a Mobotix, with MX two wire adaptors. Like I said, I will have more info probably late this weekend.
 

·
Contractor of the Month
Joined
·
26,075 Posts
Hey guys, I am going to follow up on this. Free time just came to an end and we are booked for the rest of the week, through the week end. I will come back with diagrams and particulars.

The camera system is a Mobotix, with MX two wire adaptors. Like I said, I will have more info probably late this weekend.
That's Mx2wire, it's all IP based communication over LAN.

Good system, the doorbell controller is IP to dry contact relay IIRC.

Still wouldn't use the term virtual circuit...but whatever it's all semantics.
 
1 - 5 of 5 Posts
Top