STOP 2nd phone line from ringing

[Honeymonkey]

I wonder if anyone has an idea how to prevent a phone from sensing the ring signal.
Here is the reason.
My voip provider (phonepower) has a box that line one and line two plug into. Phonepower provides a cloned 2nd line for free so if someone is on line 1, you can click over to line 2 and make a call. The big problem is when phonepower rings my phone, both lines ring, first one, then the next. Very annoying and phonepower has no provision to stop line 2 from ringing.
My thoughts are to build a circuit on line 2 after it exits the phonebox to silence the ring signal, but still allow me to get a dial tone when needed.
I find many circuits to make a phone ring, but none to stop it.

Is it as simple as rectifying the ac voltage? Or will this cause other problems with all the connected phones?
Any ideas?

 

[AnalogKid]

If the phone has a ringer that is separate from the receiver (speaker), then disconnecting the ring device will stop all ringing without affecting any other functions in that or other phones.

ak

 

[Honeymonkey]

If the phone has a ringer that is separate from the receiver (speaker), then disconnecting the ring device will stop all ringing without affecting any other functions in that or other phones.

ak

Thanks for the reply, but it is not that simple. Line 2 comes out of the voip phonebox which connects to my punchdown phone block where 8 phones are connected. In other words, what comes out of this box feeds all the phones in the house.

My thought is if I can put a circuit in series with the line 2 only pair that comes out of this phonepower box it will supress all the line 2 ringers on the phones downline, but leave line one ringers alone. (Line 1 and 2 are on different pairs)

 

[Bluejets]

Draw a circuit of what you have. Normally ring voltage is much higher than line. Also depends on what country you are in as to origin of tone.e.g. here in Aus everything comes from within the modem (NBN).

 

[davenn]

Draw a circuit of what you have. Normally ring voltage is much higher than line. Also depends on what country you are in as to origin of tone.

again ... this is a VoIP system

there is no separate ringing /line voltage
it's ALL digital signalling and voice

the phones have their own IP address and are basically connected directly to the internet

 

[JWHassler]

When VOIP phones went in here (California), the modem had an output ffor POT units that preserves the use of existing phones.

 

[AnalogKid]

If there is no ring signal, but only a ring code (a pretty important detail to leave out), then the only way to stop ringing is to examine the code as it goes by, looking for the ring code, and setting the ring code to non-ring before passing it on to the phones.

ak

 

[Honeymonkey]

When VOIP phones went in here (California), the modem had an output ffor POT units that preserves the use of existing phones.

You are correct. Each phone is NOT connected to the internet. The modem does have a POT output which all the existing old style telephones connect to. As I said, on the back of the modem phone box there is 2 POT jacks (line one and line 2)
This is USA phone system, so if there was a way to prevent an old style phone from ringing, I am pretty sure it would apply here. Just forget I mentioned VOIP, as I am pretty sure that after it comes out of the modem phonebox, it is just POTS

 

[AnalogKid]

Completely eliminating the ring signal would be difficult. What you can do is detect a certain voltage level that reliably reflects the start of ringing, and use that detection to disconnect the downstream phones for 1-2 seconds. If you answer the phone in the middle of a ring, you would not be connected until the 1-2 seconds timed out. Depending on the ring pattern, the timer could be tweaked pretty close to the actual ring burst time.

A potential problem is that the off-hook voltage is significantly lower than the on-hook. This means the ring detector can't look in that direction, or it will disconnect a phone as soon as it is picked up. If the ring voltage starts with a negative half cycle, that will be missed by the detector. Depending on the type and sensitivity in the phones there might be a chirp, but not a full ring.

Note - discussing phone line voltage polarities gets messy because the original system runs on -48 V wrt earth ground, but some new systems that are isolated from the phone system, such as voip phones, use +48 V.

ak

 

[Honeymonkey]

Completely eliminating the ring signal would be difficult. What you can do is detect a certain voltage level that reliably reflects the start of ringing, and use that detection to disconnect the downstream phones for 1-2 seconds. If you answer the phone in the middle of a ring, you would not be connected until the 1-2 seconds timed out. Depending on the ring pattern, the timer could be tweaked pretty close to the actual ring burst time.

A potential problem is that the off-hook voltage is significantly lower than the on-hook. This means the ring detector can't look in that direction, or it will disconnect a phone as soon as it is picked up. If the ring voltage starts with a negative half cycle, that will be missed by the detector. Depending on the type and sensitivity in the phones there might be a chirp, but not a full ring.

Note - discussing phone line voltage polarities gets messy because the original system runs on -48 V wrt earth ground, but some new systems that are isolated from the phone system, such as voip phones, use +48 V.

ak

Doesnt the voltage chance from dc to ac to initiate the ring and it is the ac that the phones detect that starts the ring? Since I never want line 2 to ring ( can only make outgoing calls on a cloned line), can I not supress the ac so the phones on line 2 will only see a voltage rise and not ac?
Not sure if that would be a direction to look.

 

[AnalogKid]

When a phone is on hook voltage is 48 V, continuously. The 90 Vrms ring tone is superimposed on this. The 48 V is not a hard-regulated power supply output, but a 48 V source through an impedance such as 900 ohms. When a phone goes off hook, it loads this soft voltage source and pulls the line voltage down to around 8 Vdc, with about 1/2 volt of bidirectional audio riding on it.

https://en.wikipedia.org/wiki/Ringing_(telephony)

The audio on a phone line also is AC, and is bidirectional, so suppressing (a lot) one frequency in one direction while leaving the bidirectional other frequencies alone would be difficult.

Pretty good overview: http://www.epanorama.net/circuits/teleinterface.html

ak

 

[Honeymonkey]

When a phone is on hook voltage is 48 V, continuously. The 90 Vrms ring tone is superimposed on this. The 48 V is not a hard-regulated power supply output, but a 48 V source through an impedance such as 900 ohms. When a phone goes off hook, it loads this soft voltage source and pulls the line voltage down to around 8 Vdc, with about 1/2 volt of bidirectional audio riding on it.

https://en.wikipedia.org/wiki/Ringing_(telephony)

The audio on a phone line also is AC, and is bidirectional, so suppressing (a lot) one frequency in one direction while leaving the bidirectional other frequencies alone would be difficult.

Pretty good overview: http://www.epanorama.net/circuits/teleinterface.html

ak

Thanks, after reading all that, I can see how it would be impractical and difficult. Since it is only the time line one is ringing that I need to supress line 2 ringer, I will probably make something that disconnects all the phones on line two while line one rings, then simply reconnect them after line one stops ringing. Or someone picks up.

 

[AnalogKid]

Do you know what the ring voltage frequency is? With the right relay, this can be done with zero active components:
Capacitor
Diode bridge
Filter capacitor
Relay coil

ak

 

[Honeymonkey]

Do you know what the ring voltage frequency is? With the right relay, this can be done with zero active components:
Capacitor
Diode bridge
Filter capacitor
Relay coil

ak

Not off hand. I will have to do a bit more reading on united states pot service when I get a chance. I have a bit of a raid problem to deal with at the moment.