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Creative customer - 1 line, 2 buildings #181187 09/24/08 08:41 PM
Joined: Jan 2005
Posts: 109
Grover Offline OP
Member
Some time ago, I installed conduit and pulled CAT5 underground from a utility building - 250' in one direction to his office, and 250' in another direction to his house.

Now he's had the phone line installed (aerial - about a mile) to the utility building. I've got dial tone at both the house and the office.

He wants a way to signal from the office to the house if the call is for his wife, and vice versa!

I'm stuck! Any ideas? Can I use another pair and have 2 line phones at each end? No dial tone, but how do I ring?

Thanks!

Grov

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Re: Creative customer - 1 line, 2 buildings [Re: Grover] #181188 09/24/08 08:45 PM
Joined: Jul 2004
Posts: 9,569
G
gfretwell Offline
Member
With all the wonderful things phones do these days I would look at what they sell first. There may be a phone product out there with intercom capability.


Greg Fretwell
Re: Creative customer - 1 line, 2 buildings [Re: gfretwell] #181189 09/24/08 09:48 PM
Joined: Nov 2005
Posts: 823
J
JoeTestingEngr Offline
Member
2 starter's pistols ought to do it.
Joe

Re: Creative customer - 1 line, 2 buildings [Re: JoeTestingEngr] #181200 09/25/08 05:00 AM
Joined: Jul 2002
Posts: 8,379
Trumpy Offline
Member
Thought about a cheap pair of UHF CB hand-helds?

Re: Creative customer - 1 line, 2 buildings [Re: gfretwell] #181204 09/25/08 06:02 AM
Joined: Jan 2005
Posts: 109
Grover Offline OP
Member
Good idea - Google came up pretty dry - apartment entry stuff....

Grov

Re: Creative customer - 1 line, 2 buildings [Re: JoeTestingEngr] #181206 09/25/08 06:54 AM
Joined: Jan 2005
Posts: 109
Grover Offline OP
Member
Good one! Would probably scare the horses tho... and give a whole new meaning to acoustic ceiling :-)

Grov

Re: Creative customer - 1 line, 2 buildings [Re: Grover] #181218 09/25/08 07:25 PM
Joined: Nov 2005
Posts: 823
J
JoeTestingEngr Offline
Member
Well if I was going to do it....
Possibility #1: I would build two hi-z bridging circuits, one for each end. Follow that with two tone decoders or one DTMF decoder. Set decoders for or use # or * outputs. Press # or * on either end and audible goes off on both ends.

Possibility #2: Build a hi-z bridging DC voltage detector circuit for both ends. Also use a button with a loading resistance on each side. On hook voltage would be the highest. Check typical off-hook voltage with one and then both phones off-hook. Set the detectors to drive a piezo a volt or so below the voltage measured, but not at zero volts. (Unless you want both audibles to go off if you lose your phone lines. Pick the series resistance with the N.O. pushbutton to load the phone line below the threshold of the detectors.

But that's just what I would do if I had only one active line. But if you have 1 or 2 free pairs and a couple wall warts, there are many other opyions.
Joe

Re: Creative customer - 1 line, 2 buildings [Re: JoeTestingEngr] #181223 09/25/08 11:17 PM
Joined: Mar 2007
Posts: 404
noderaser Offline
Member
Why not get a cheap pair of FM intercoms?

Re: Creative customer - 1 line, 2 buildings [Re: JoeTestingEngr] #181241 09/26/08 11:10 AM
Joined: Jul 2004
Posts: 783
L
LarryC Offline
Member
Use the AC powered series circuit with the diode across each switch and each lamp. Replace the lamp with a DC coil relay to drive an audio alarm at each end. Power it with a wall wart and you are done.

Larry C

Re: Creative customer - 1 line, 2 buildings [Re: LarryC] #181245 09/26/08 01:08 PM
Joined: Oct 2006
Posts: 745
E
EV607797 Offline
Member
Most office products stores sell AT&T 4-line phones with intercom capability. They can be used with one single line, as long as it is on line one. As long as the wiring between them isn't more than 600 feet, they will allow calls to be answered, placed on hold and picked up at stations in other locations or buildings. They also offer intercom which is actually FM riding along the cable pair being used for line 1.


---Ed---

"But the guy at Home Depot said it would work."
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