I was wondering if it would be possible to hook 2 POTS phones togeather
witout the telephone network. What voltage is required to run a phone and
what voltage is required to make it ring? I think it is somewhere around
18vac and 55vac to ring but I was a kid playing with a voltmeter when I
took those voltages so I'm not sure what the exact voltages were. I guess I
could just find out with my voltmeter but I was wondering if there was
anything else needed other than approx 18vac and a wire between the two.

Thanks,
Mike

Michael Kennedy wrote:
I was wondering if it would be possible to hook 2 POTS phones togeather
witout the telephone network. What voltage is required to run a phone and
what voltage is required to make it ring? I think it is somewhere around
18vac and 55vac to ring but I was a kid playing with a voltmeter when I
took those voltages so I'm not sure what the exact voltages were. I guess I
could just find out with my voltmeter but I was wondering if there was
anything else needed other than approx 18vac and a wire between the two.

Thanks,
Mike

You can use two telephones to talk, but you will have to shout to the
other end to get the person to pick up the phone. It is 90VAC at 20 Hz
for ringing, and 24-48 volts DC to power the electronics in the phone.
Some cheap personal radio service walkie-talkies would be better unless
your house is made from shielding wall and floor and ceiling materials.
Foil-covered sheet rock is normally used only for Kitchen walls, so
you should be aboe to use the psesonal radios anywhere. In addition to
24-48Vdc to run the telephones, you have to have wires, etc that are a
pain.

If you do go the telephone route, some phones are polarity sensitive to
operate the touchtone dialing signals, but you don't neet them so it is
not a big deal. I would take any power supply 24 - 48 VDC and put the
power supply in series with the two telelpohones that are also
connected in series, Then bypass the power supply with a 10 uF or
larger capacitor of 50VDC or higher rating. This makes the power
supply a low impedance to the talking frequencies.

I designed telco central office circuits for Bell Labs/AT&T 40+ years
ago and did what you are proposing doing for a home novelty. But, the
radios are far easier, have internal signalling, don't tie you down to
one location, can be used for car caravanning, skiing trips, and all
sorts of other things and are not very $$. Available at sportuing
goods and Radio Shack stores.

H. R.(Bob) Hofmann

wrote:
Michael Kennedy wrote:

I was wondering if it would be possible to hook 2 POTS phones togeather
witout the telephone network. What voltage is required to run a phone and
what voltage is required to make it ring? I think it is somewhere around
18vac and 55vac to ring but I was a kid playing with a voltmeter when I
took those voltages so I'm not sure what the exact voltages were. I guess I
could just find out with my voltmeter but I was wondering if there was
anything else needed other than approx 18vac and a wire between the two.

Thanks,
Mike


You can use two telephones to talk, but you will have to shout to the
other end to get the person to pick up the phone. It is 90VAC at 20 Hz
for ringing, and 24-48 volts DC to power the electronics in the phone.
Some cheap personal radio service walkie-talkies would be better unless
your house is made from shielding wall and floor and ceiling materials.
Foil-covered sheet rock is normally used only for Kitchen walls, so
you should be aboe to use the psesonal radios anywhere. In addition to
24-48Vdc to run the telephones, you have to have wires, etc that are a
pain.

If you do go the telephone route, some phones are polarity sensitive to
operate the touchtone dialing signals, but you don't neet them so it is
not a big deal. I would take any power supply 24 - 48 VDC and put the
power supply in series with the two telelpohones that are also
connected in series, Then bypass the power supply with a 10 uF or
larger capacitor of 50VDC or higher rating. This makes the power
supply a low impedance to the talking frequencies.

I designed telco central office circuits for Bell Labs/AT&T 40+ years
ago and did what you are proposing doing for a home novelty. But, the
radios are far easier, have internal signalling, don't tie you down to
one location, can be used for car caravanning, skiing trips, and all
sorts of other things and are not very $$. Available at sportuing
goods and Radio Shack stores.

H. R.(Bob) Hofmann


Hi...

Or see if he can't find a couple of the old mag sets

Ken

Well I have an out building with cat 5 running to it for a network. I'm
using only 4 of the 8 wires and I figured that I'd use 2 for a telephone
line and 2 for an intercom since I have a 2 line phone. I have radios but
keeping batteries in them is a pain and this phone has speakerphone and a
headset.

I can't imagine any easy way to produce a 90v 20hz signal. Hmm...


"Ken Weitzel" wrote in message
news:LW00f.51769$1i.10322@pd7tw2no...


wrote:
Michael Kennedy wrote:

I was wondering if it would be possible to hook 2 POTS phones togeather
witout the telephone network. What voltage is required to run a phone and
what voltage is required to make it ring? I think it is somewhere around
18vac and 55vac to ring but I was a kid playing with a voltmeter when I
took those voltages so I'm not sure what the exact voltages were. I guess
I
could just find out with my voltmeter but I was wondering if there was
anything else needed other than approx 18vac and a wire between the two.

Thanks,
Mike


You can use two telephones to talk, but you will have to shout to the
other end to get the person to pick up the phone. It is 90VAC at 20 Hz
for ringing, and 24-48 volts DC to power the electronics in the phone.
Some cheap personal radio service walkie-talkies would be better unless
your house is made from shielding wall and floor and ceiling materials.
Foil-covered sheet rock is normally used only for Kitchen walls, so
you should be aboe to use the psesonal radios anywhere. In addition to
24-48Vdc to run the telephones, you have to have wires, etc that are a
pain.

If you do go the telephone route, some phones are polarity sensitive to
operate the touchtone dialing signals, but you don't neet them so it is
not a big deal. I would take any power supply 24 - 48 VDC and put the
power supply in series with the two telelpohones that are also
connected in series, Then bypass the power supply with a 10 uF or
larger capacitor of 50VDC or higher rating. This makes the power
supply a low impedance to the talking frequencies.

I designed telco central office circuits for Bell Labs/AT&T 40+ years
ago and did what you are proposing doing for a home novelty. But, the
radios are far easier, have internal signalling, don't tie you down to
one location, can be used for car caravanning, skiing trips, and all
sorts of other things and are not very $$. Available at sportuing
goods and Radio Shack stores.

H. R.(Bob) Hofmann


Hi...

Or see if he can't find a couple of the old mag sets

Ken

Michael Kennedy wrote:

Well I have an out building with cat 5 running to it for a network. I'm
using only 4 of the 8 wires and I figured that I'd use 2 for a telephone
line and 2 for an intercom since I have a 2 line phone. I have radios but
keeping batteries in them is a pain and this phone has speakerphone and a
headset.

I can't imagine any easy way to produce a 90v 20hz signal. Hmm...

Hi Michael...

Just for the heck of it, in case you're a younger fellow, a mag set is
a self contained single telephone set. Doing remote radio broadcasts
for instance we'd rent two pairs from the local telco. One audio
quality for the actual broadcast, and one DC pair. Just a pair of
wires from the remote site back to the station control room. To each
end we'd connect a "mag set". Crank the handle on the set, and ac
would be generated that "rang" the other end.

However, enough old man tales of the olden days, how about an
alternative suggestion, if I may?

Take a look at the new'ish two set cordless phones. Cheap now.
Plug the first one into the house line, use one set in the house.
Plug the second set base into ac in your outbuilding. You then have
a telephone set to use there, and an intercom between the outbuilding
and house. Transfer calls back and forth between handsets, do three way
calls. They're great! (I use a pair at the lake, one in the cottage,
the other in the boathouse)

The only downside I can think of is that a power failure disables them.

Just a suggestion.

Ken

Hey I know where to get a magset I just didn't know that was what it was
called! Anyway I live 30 minutes away from Skycraft. They are a big surplus
dealer which has anything you need to build about anything... Well almost. I
have tallked with people all around the US and quite a few know of it so I
guess that it is sort of unique. Anyhow that sounds like a good way to
generate the 90v so long that it is 20hz
Thanks,
Mike
"Ken Weitzel" wrote in message
news:Vb20f.50560$oW2.21405@pd7tw1no...


Michael Kennedy wrote:

Well I have an out building with cat 5 running to it for a network. I'm
using only 4 of the 8 wires and I figured that I'd use 2 for a telephone
line and 2 for an intercom since I have a 2 line phone. I have radios but
keeping batteries in them is a pain and this phone has speakerphone and a
headset.

I can't imagine any easy way to produce a 90v 20hz signal. Hmm...

Hi Michael...

Just for the heck of it, in case you're a younger fellow, a mag set is
a self contained single telephone set. Doing remote radio broadcasts for
instance we'd rent two pairs from the local telco. One audio quality for
the actual broadcast, and one DC pair. Just a pair of
wires from the remote site back to the station control room. To each
end we'd connect a "mag set". Crank the handle on the set, and ac
would be generated that "rang" the other end.

However, enough old man tales of the olden days, how about an
alternative suggestion, if I may?

Take a look at the new'ish two set cordless phones. Cheap now.
Plug the first one into the house line, use one set in the house.
Plug the second set base into ac in your outbuilding. You then have
a telephone set to use there, and an intercom between the outbuilding
and house. Transfer calls back and forth between handsets, do three way
calls. They're great! (I use a pair at the lake, one in the cottage, the
other in the boathouse)

The only downside I can think of is that a power failure disables them.

Just a suggestion.

Ken

Michael Kennedy ha escrito:

Hey I know where to get a magset I just didn't know that was what it was
called! Anyway I live 30 minutes away from Skycraft. They are a big surplus
dealer which has anything you need to build about anything... Well almost. I
have tallked with people all around the US and quite a few know of it so I
guess that it is sort of unique. Anyhow that sounds like a good way to
generate the 90v so long that it is 20hz

Michael,
try this:
http://www.epanorama.net/documents/t..._intercom.html

regards, Ben

b wrote:
Michael Kennedy ha escrito:


Hey I know where to get a magset I just didn't know that was what it was
called! Anyway I live 30 minutes away from Skycraft. They are a big surplus
dealer which has anything you need to build about anything... Well almost. I
have tallked with people all around the US and quite a few know of it so I
guess that it is sort of unique. Anyhow that sounds like a good way to
generate the 90v so long that it is 20hz


Michael,
try this:
http://www.epanorama.net/documents/t..._intercom.html

regards, Ben

I don't know if I'd run 90vac down the same cable as my network, but it
actually 'should' work.

In my case, I took a couple of 'power line' intercoms and modified them
to use the phone line instead. I see them all the time at thrift stores
for less than $5 apiece. Disconect the FR output to the AC cord, and
solder on a phone plug (or jack, if you want to get fancy). Route that
signal (RF) down a pair on your Cat 5.

Works for me....

jak

Well if that is the voltage that the phone uses I've done it many times.
without any problems : )
- Mike

a"jakdedert" wrote in message
...
b wrote:
Michael Kennedy ha escrito:


Hey I know where to get a magset I just didn't know that was what it was
called! Anyway I live 30 minutes away from Skycraft. They are a big
surplus
dealer which has anything you need to build about anything... Well
almost. I
have tallked with people all around the US and quite a few know of it so
I
guess that it is sort of unique. Anyhow that sounds like a good way to
generate the 90v so long that it is 20hz


Michael,
try this:
http://www.epanorama.net/documents/t..._intercom.html

regards, Ben

I don't know if I'd run 90vac down the same cable as my network, but it
actually 'should' work.

In my case, I took a couple of 'power line' intercoms and modified them to
use the phone line instead. I see them all the time at thrift stores for
less than $5 apiece. Disconect the FR output to the AC cord, and solder
on a phone plug (or jack, if you want to get fancy). Route that signal
(RF) down a pair on your Cat 5.

Works for me....

jak

Michael Kennedy wrote:

I was wondering if it would be possible to hook 2 POTS phones togeather
witout the telephone network. What voltage is required to run a phone and
what voltage is required to make it ring? I think it is somewhere around
18vac and 55vac to ring but I was a kid playing with a voltmeter when I
took those voltages so I'm not sure what the exact voltages were. I guess I
could just find out with my voltmeter but I was wondering if there was
anything else needed other than approx 18vac and a wire between the two.

Thanks,
Mike


Michael, I have some power supplies from the old 1A2 Key telephone
systems that supply the DC talk voltage, and also have a subcycle 20 Hz
ring generator if you want one. I'm not far from you, just north of
Belleview on Hwy 441.

--
?

Michael A. Terrell
Central Florida

wrote:


Michael Kennedy wrote:
I was wondering if it would be possible to hook 2 POTS phones togeather
witout the telephone network. What voltage is required to run a phone and
what voltage is required to make it ring? I think it is somewhere around
18vac and 55vac to ring but I was a kid playing with a voltmeter when I
took those voltages so I'm not sure what the exact voltages were. I guess
I could just find out with my voltmeter but I was wondering if there was
anything else needed other than approx 18vac and a wire between the two.

Thanks,
Mike

You can use two telephones to talk, but you will have to shout to the
other end to get the person to pick up the phone. It is 90VAC at 20 Hz
for ringing, and 24-48 volts DC to power the electronics in the phone.
Some cheap personal radio service walkie-talkies would be better unless
your house is made from shielding wall and floor and ceiling materials.
Foil-covered sheet rock is normally used only for Kitchen walls, so
you should be aboe to use the psesonal radios anywhere. In addition to
24-48Vdc to run the telephones, you have to have wires, etc that are a
pain.

If you do go the telephone route, some phones are polarity sensitive to
operate the touchtone dialing signals, but you don't neet them so it is
not a big deal. I would take any power supply 24 - 48 VDC and put the
power supply in series with the two telelpohones that are also
connected in series, Then bypass the power supply with a 10 uF or
larger capacitor of 50VDC or higher rating. This makes the power
supply a low impedance to the talking frequencies.

I designed telco central office circuits for Bell Labs/AT&T 40+ years
ago and did what you are proposing doing for a home novelty. But, the
radios are far easier, have internal signalling, don't tie you down to
one location, can be used for car caravanning, skiing trips, and all
sorts of other things and are not very $$. Available at sportuing
goods and Radio Shack stores.

H. R.(Bob) Hofmann

If I understand correctly, you suggest connecting a 48V power supply across
the series combination of the two phones. I believe that in addition to
the power supply, you probably need a current limiting resistor. The phone
system must get shorted quite often and they wouldn't want the wires to
melt when this happens. I think the phones might rely on the current being
limited. I think that the phone loads the line so that it has an off-hook
voltage of about 6V or so, on a normal phone line, but you could check this
and you could even measure the off-hook current in a phone too.
Chris

Chris - You are correct. There is impedance built into the central
office supply system to limit the current to about 100 ma as I
remember. I did this work 40 yhears ago when I first joined Bell LAbs,
been doing EMC work since 1970 or so. You can put a 1000 ohm resistor
in series with the two phones and the power supply, and then bypass the
resistor with a 10 uf electrolytic polarized correctly so there are no
audio losses across the resistor.

Bob Hofmann