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DBN1101 Ericsson phone to intercom

Started by AlexL, November 13, 2022, 04:18:03 PM

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AlexL

Hi,

I have a DBN1101 Ericsson phone that I would like to repurpose as an intercom. Is there any way to connect the phone so that it just rings if someone buzzes our apartment number? Here are the pictures of the phone in question and the current intercom.

Thanks!

TelePlay

What voltage and A/C frequency are being used to ring the intercom buzzer in your apartment?
Yesterday eats you up, it eats everyone up . . .

AlexL


TelePlay

As your apt super.

Probably 60 Hz and 18 VAC.

Your phone requires 90 VAC, or so, at 20 Hz to operate the ringer.

I don't think you can do what you want directly.

However, your intercom power could be used to trip a relay which could turn on a ring generator connected to your phone's ringer. That would leave the problem of interfacing the phone's handset to the intercom talk circuit.

Maybe someone else on the forum has done all this and can explain how they did it.
Yesterday eats you up, it eats everyone up . . .

dsk

When I lived in a flat with door phone I managed to use a regular phone, but that was a quite different system. Some intercoms use one common, one for the transmitter, one for the receiver, one for the ringer, one for the door opener button.  Some does only use 2 or 3 wires. 
We need to know a lot more about your phone to be able to help.
Looks like your system may use many wires.

AlexL

From what I can tell from researching online, these are the Fermax (interphone) connections:
Link (Spanish)

1. door opener button (not in use)
2. Mic
3. common
4. buzzer call
6. Speaker (downstairs)

I also sent an email to Fermax asking for a circuit diagram. @dsk - If I am not mistaken, it seems very similar to what you're describing.

@ TelePlay - Unfortunately my super doesn't know.

dsk

Try common to terminal 3
The on from transmitter in the handset 6  to the one you find is to the transmitter. 
Disconnect 2 (From handset receiver) and connect that one to the one you find is to the receiver. 

Try if you may speak with the other end, and may receive.  Check out if it is disconnected when you go on hook (press the hook down and try if you here something, or they hear you in the other end. )

If it works the next is to get some kind of ringing. If it doesent work put the wires back again.

TelePlay

Do a Google search for "fermax nr 0208 wiring diagram"

Looks like it's a 12 VAC system.
Yesterday eats you up, it eats everyone up . . .

markosjal

#8
Quote from: TelePlay on November 13, 2022, 09:41:41 PMAs your apt super.

Probably 60 Hz and 18 VAC.

Your phone requires 90 VAC, or so, at 20 Hz to operate the ringer.

I don't think you can do what you want directly.

However, your intercom power could be used to trip a relay which could turn on a ring generator connected to your phone's ringer. That would leave the problem of interfacing the phone's handset to the intercom talk circuit.

Maybe someone else on the forum has done all this and can explain how they did it.


Not entirely accurate. You can trigger a ring generator with whatever ring voltage is produced by the intercom you may need to do this by way of a relay.
Ring generators on eBay:
https://www.ebay.com/itm/252707205895
https://www.ebay.com/itm/144677759472
https://www.ebay.com/itm/253414551080

You should probably first verify what kind of ringer that phone has (may be European at 25Hz or from Mexico at 20 Hz) and in fact that you can make it ring and the ringer works. The phone says made in Medellin (Colombia) which if it was made to be used in Colombia they use a 20 Hz power line frequency and it therefore probably should ring at 20 Hz. That however is not a given as some areas in Mexico used 25Hz ringers even though it is a 60Hz country.

If you can find a ring generator near the voltage of the intercom system and the intercom system can provide the current for the ring generator you may not need a relay but I would probably use a(n electronic) relay to be safe.

then it is only a matter of connecting the audio which is probably the easiest part.
Phat Phantom's phreaking phone phettish

markosjal

Quote from: AlexL on November 13, 2022, 08:50:23 PMHow can I check both values?

Put your tongue on the wires and have someone ring you.

NO DO NOT DO THAT!

Use a volt meter instead of your tongue.
Phat Phantom's phreaking phone phettish

dsk

Not easy to find good information about those details on net, but it seems like the maser unit is made for 12v backup battery.

The Ericsson ringers are usually not sensitive to frequencies and should work between 15 and 30 Hz.  If you have around 12-20V 50 or 60 Hz it may be possible by putting the 2 coils in parallel. (with the right polarity on both coils).  Then adjusting the bells closer to the "hammer" and you will get some kind of ringing.   Ericsson made some of their PAX's for mains frequency, and considerably lower voltage then 70V.   You may test it "as is" with mains frequency and lower voltage.  I have got 2 or 3 1000 ohms ringers in series with 1uF (original) capacitor to ring at 50Hz and 24V .... still a way down to 12V :)  But as someone mentioned a relay and ring current source should work.


TelePlay

Long time ago I made a hand held ring generator box using a DSine ring generator and a set of four (in parallel) A23 12 volt batteries

http://www.classicrotaryphones.com/forum/index.php?topic=26226.msg255310#msg255310

with a momentary push button switch and 4 types of output connectors, mod Jack, RCA, banana plug and bare wire (they make interconnect wires with banana plugs on one end and alligator clips on the other - the best use for testing ringers in or out of phones, modular jack next).

I see from the links above they also make one that is 24 VDC version now.

I don't see any that work off of AC voltage. That intercom system seems to work on 12 VAC with possibly a 12 VDC back up supply. Don't know which parts or features of the intercom will and/or will not work with battery back up power.

How to ring the phone depends on the buzzer voltage and type sent to the apartment intercom. As said above, the talk element connections should be quite simple.


Yesterday eats you up, it eats everyone up . . .

markosjal

iT does not matter if the intercom buzzes from AC or DC . if AC, Put a bridge rectifier on it with a Capacitor across it's output and a Solid State relay . For DC trigger a solid state relay directly. This Solid state relay can then trigger a ring generator of your preference. It's not rocket science.
Phat Phantom's phreaking phone phettish

TelePlay

Quote from: markosjal on November 15, 2022, 04:44:13 PMiT does not matter if the intercom buzzes from AC or DC . if AC, Put a bridge rectifier on it with a Capacitor across it's output and a Solid State relay . For DC trigger a solid state relay directly. This Solid state relay can then trigger a ring generator of your preference. It's not rocket science.

Exactly, well said.
Yesterday eats you up, it eats everyone up . . .