Help with Alarm I/O Wires

jzobel

n3wb
Nov 16, 2021
29
6
NY
I have the SD49225XA-HNR PTZ. I am trying to work the the alarm I/O wires to trip a door bell sensor during motion as I am at an off grid location and not using BI. This model has 5 wires.
Alarm Out
Alarm Com
Alarm Ground
Alarm In 1
Alarm In 2

Using this doorbell

I am confused as to why it has both Alarm Out and Alarm COM. The amperage of the chime is so low I doubt I need a relay. It has 4 wires. Looks like + and - , then simple contact switch wires. Is it correct to assume both the Out and COM wires have zero pass through voltage and should supply the chime its own power?

Should I use the Alarm Out and Ground. Or the Alarm COM and Ground?
 
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You want your ding-dong to activate during an event? The alarm IN/OUT are dry-contacts. Normally the alarm ground is for the input side, while the alarm common is for the output side. If you have an ohm-meter, better confirm, but the output could be “floating” to comply with your particular application. In your case, use the Alarm-Out and Alarm-COMM, connected between the green cable, an the other end to ground. You will need 12V constant (500mA is enough) at your ebay doorbell, while connecting the green cable to GND (-12V), in order to activate the ding-dong (no need for the yellow cable). Remember to login (WEB) for the alarm-setup event (normally open).
 
Awesome. I never would have known not to use the alarm ground. One thing, if wiring the ding dong to 12v red and black. The green and yellow activate it when connected. So to be clear I don’t want to use alarm out and alarm com connected to yellow and green? And just red black to 12v source? I believe you entirely. But if the alarm out is a simple dry relay why doesn’t that setup work?
Thanks
 
I understand you need the constant 12V for power, while the Green is for triggering. Not sure about the yellow cable. I installed a similar bell at an office front desk, using only the green cable (plus power). It was a long time, but I could check my notes. If you have an ohm-meter, check for continuity between both cables. It could be at ground level (the yellow one)
 
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Awesome. I never would have known not to use the alarm ground. One thing, if wiring the ding dong to 12v red and black. The green and yellow activate it when connected. So to be clear I don’t want to use alarm out and alarm com connected to yellow and green? And just red black to 12v source? I believe you entirely. But if the alarm out is a simple dry relay why doesn’t that setup work?
Thanks

not sure if I answered your question in the above post. A drawing could help
 
I understand you need the constant 12V for power, while the Green is for triggering. Not sure about the yellow cable. I installed a similar bell at an office front desk, using only the green cable (plus power). It was a long time, but I could check my notes. If you have an ohm-meter, check for continuity between both cables. It could be at ground level (the yellow one)
FWIW, a similar ad in eBay shows constant 12VDC to red (+) and black (-) then push button "makes" green and yellow, as below:

s-l500 (1).jpg eBay-chime2.jpeg
 
Yes...this is what I considered. Thank you. But I will have to test. Because your first version could also be right. As it appears they can sometimes be wired to have 2 switches. I guess front door & back door, haha. So effectively the green or the yellow may work the same, but just by using one or the other. I was so thrown off because most of the alarm out wires, look like the ones below.


This arrangement had Alarm Out instead of Alarm NO, which I bet are the exact same.
 
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Yes...this is what I considered. Thank you. But I will have to test. Because your first version could also be right. As it appears they can sometimes be wired to have 2 switches. I guess front door & back door, haha. So effectively the green or the yellow may work the same, but just by using one or the other. I was so thrown off because most of the alarm out wires, look like the ones below.


This arrangement had Alarm Out instead of Alarm NO, which I bet are the exact same.
For the record, it's @eggsan that has used the chime in the past; I'm just a meddler onlooker.:cool:
 
FWIW, a similar ad in eBay shows constant 12VDC to red (+) and black (-) then push button "makes" green and yellow, as below:

View attachment 164307 View attachment 164308
Just check my notes. Yes, the yellow cable is at the same potential as the green, actually both at 0 volts (ground). It would be the same as bring the green cable to either yellow or green. TonyR is better suited for your application, in which you may used the camera 12v (if available), while using the yellow/green for contact (N.O.)
 
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Yes...this is what I considered. Thank you. But I will have to test. Because your first version could also be right. As it appears they can sometimes be wired to have 2 switches. I guess front door & back door, haha. So effectively the green or the yellow may work the same, but just by using one or the other. I was so thrown off because most of the alarm out wires, look like the ones below.


This arrangement had Alarm Out instead of Alarm NO, which I bet are the exact same.
You may connect it either way. In my case, it was a matter of cabling availability (only three, power and trigger) at the end point
 
Some models have a different ring tone for the back door so you can tell where the visitor is. The green may give you a different tone from the yellow.

jzobel particular doorbell is a single tone 12v ding-dong device. The yellow/green cables are only for triggering a single door. If you need to add a second door, a mechanical doorbell (16Vac transformer) could do the job.

 
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