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Wiring Old Phone as doorbell ringer.

Started by FEgerer, February 03, 2023, 11:22:53 AM

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Good Morning,
   Good Morning, I new to the forum and was soliciting advice?  I am working on a project to take my grandfathers old NC802000 CXX rotary phone and connect it through my doorbell ringer. (IE use the phone ringer as a functional doorbell). The Doorbell is a Hikvision DS-KB8113-IME1 that is networked to my whole security system but it does have the output for electric strike plates/mag locks or mechanical doorbells.   I am under the impression that I would need to create/integrate device(s) to provide the correct voltage and frequency to power the ringer correctly.  At this point I am in over my knowledge level and would appreciate any advice or help? 
Semper Fidelis


I can't help you on your project , but welcom on the best forum existing in this world .

Robert Gift

Can you apply the output voltage from the security system branch for mechanical doorbells to the old telephone ringer and see what happens?

Installing a rectifier would create a 30 pulse per second "signal".  Maybe that might make the bell ring and its armature rebounding could make the other bell ring.

If you still have a landline, I would have that telephone connected and working.
I'd take an educated guess but am unqualified.
When something is found the last place checked, go there first.
Lighted Princess® telephones are our favorites!
Mountain Time Zone.   Not what is indicated.


I think the phone you reference here is an Automatic Electric and I believe the XX in the model number is where the ringer frequency should be. You need to therefore open the phone and see what the frequency of the ringer is first as most of those models were clearly labelled on a yellow label on the ringer inside the phone. if it has a Ringer volume on the bottom of the phone it is most likely the standard SL or 20Hz  ringer. YOU NEEDTO KNOW THIS BEFORE ANYTHING ELSE. Ringers are marked like 20~  or 30~

Assuming is is a 20Hz ringer

Take the Mechanical doorbell output and use it to trigger a relay (by way of a bridge rectifier probably as it is likely AC out)

Then you can use the relay to trigger a ring generator
I suggest you then use divided ringing using the yellow phone wire to ring the phone

If the mechanical doorbell output voltage is 12V AC and the ring generator requires 12V DC you can skip the relay all together and use only a bridge rectifier with a BIG FAT electrolytic Capacitor across it (as a filter)

The key here is knowing what that system is designed to ring. Put a Multimeter on it and test it.  Knowing more I can give you more exact details.

I assume however that you will then also have the challenge of wanting to talk on the phone to the person at the door? You will probably also want to be able to remotely unlatch the door?

All of these things are possible the remote latch usually just needs a contact closure but you need a way to initiate it from the phone.

You probably also need to capture the audio to.from doorbell and phone so they can talk together. Your doorbell says it creates a Video stream from what I see.
Phat Phantom's phreaking phone phettish


I think I just found the EASY way so scratch what I said above and consider this EASY method

The video here is your doorbell?

If so , then it can call a "phone App" which I assume is a standard SIP phone app! That is excellent news as we would not ring to an app rather an ATA (analog Telephone adapter) which has everything needed to ring the phone and communicate 2 way.

I recommend the Grandstream HT 801 (for one phone port) or HT 802 (for 2 phone ports). It can also handle all pulse to tone conversion so that the doorbell understands the rotary dial phone.  It can also ring 20 or 25 hz bells. If you have for instance a 30Hz ringer it might be "close enough" to ring it at 25 hz. I once was ringing an Automatic Electric  25 hz ringer at 20hz and it was not as loud as it should have been but did work. An external ringer is always an option too.

It should be very easy to test with a VoIP app

You can usually get an HT 801 (single port) for under $20 on ebay

____________NEW DISCOVERY----------------------

after finding and reading the manual to that doorbell it apparently MUST register to a SIP server (not really a big deal as you can always use a commercial VoIP provider that allows free calls between accounts or a local asterisk server)

If however you register it to a VoIP provider and your internet fails the doorbell would not work. Although the advantage is that you could then ring to a ring group and dial for instance your cell phone number in addition to the local extension

In my opinion it is always better to simply dial a SIP URI like 1234@ on your LAN in this kind of instance, but this device apparently will not allow that.

Attached is the SIP settings from the manual. A newer firmware version might have other options , like the option to not have to register.
If you want to proceed

1) check the ringer frequency by opening the phone

2) set up free account at

3) install a VoIP (SIP)  app for testing on your smartphone (before you buy a Grandstream Handytone)

I can help further if you need it.
Phat Phantom's phreaking phone phettish


The biggest challenge in this that I see is what I call "Cheap Chinese Firmware" Which generally means that most of the Chinese branded products do not have very good firmware and has not been widely tested for interoperability.  This believed limitation is supported by the very limited SIP settings in the device.

Personally when I see a name like "HKVision" I usually figure it is better to hold off and get something of a more reputable brand as the difference very much often is in the firmware. Believe me I am NOT talking Amazon as they are even worse than many Chinese brands as far as tech companies go. Amazon has NO INTERPERABILITY as they only want to sell you THEIR products and service.

Years ago I bought a Fanvil SIP doorbell and installed it at the gate for a client. I wanted it to simply dial a SIP URI with no registration to a server. That was not possible with the firmware despite the implication that it was in the documentation. The firmware installed was horrible and once I pointed out the deficiencies to Fanvill they had a brand new firmware update to me inside of days. I was quite shocked as I did not expect that from them so they now hold a higher status on my list. As I recall the original firmware was limited much like this HKVision.
Phat Phantom's phreaking phone phettish


Here is the phone:  There is no adjustable ringer volume (you can see the slot but no adjustment lever). Looks like the internal ringer is listed as 20hz as you predicted. 

I do not need to use it to talk through to the doorbell as there is an internal video monitor with the system that will communicate and show video.  At worst this is the doorbell, but if it does call through that is a bonus but not a requirement.  They are closing up my house this week (meaning the drywall and external stone work around the door frame) so I would need to insure I have wiring run between devices. The ringer and internal video screen are POE so they run back to the DVR for power.   
thanks again



I previously edited this but the edited version does not appear
Check your private messages. I provided a shorter solution there.

With Grandstream ATA  you can always choose to use this phone, or a different one to answer the door later, rather than being limited to a "ring only device". Using the ring generator we do not know how long it will make the phone ring for by default. Ringing a phone, it will ring till answered.

Disregard everything below but not deleting it as we may need it later.

If you use android try this free softphone

For simplicity sake set up a free account at for now and register both devices there . You can then assign an extension number to dial from one account to the other. If this seems overwhelming , let me know I would be happy to offer you 2 SIP accounts for testing. That wayy  also I can test with a client here and see if it all looks good from one end anyway.

Set the codecs for G711u and G711a (ulaw and alaw) as those are standard "voice only" codecs. You need to make absolutely sure that the doorbell will use one of these "voice only" CODECS , so test with a softphone disabling all other CODECS.

Set the "number" field in the config screen to the extension established for the SIP softphone or ATA. That tells the doorbell what to dial when it is rung.

Phat Phantom's phreaking phone phettish


I found this  link should this topic come up again!

Might be a solution for some people maybe not the best solution for this OP though
Phat Phantom's phreaking phone phettish