Telephone socket: dangerous?

[Seeker]

Where I live we have those telephone sockets that look like a "T". But new
phone cords don't use the T so we have to buy adaptors too. So when I
bought the adaptor (in which the cord plugs in - the adaptor is shaped as
a T) the salesman told me I may need to invert the polarity on the T for
it to work.

I went on and did it without taking any precautions. I had a vague feeling
that the voltage on the telephone socket is 12V. Afterwards I measured it
with my multimeter and found 50V.

Was I too careless? Was I close to the other side? What would happen if I
touched both electrodes with my finger?

 

[Don Bruder]

Where I live we have those telephone sockets that look like a "T". But new
phone cords don't use the T so we have to buy adaptors too. So when I
bought the adaptor (in which the cord plugs in - the adaptor is shaped as
a T) the salesman told me I may need to invert the polarity on the T for
it to work.

I went on and did it without taking any precautions. I had a vague feeling
that the voltage on the telephone socket is 12V. Afterwards I measured it
with my multimeter and found 50V.

Was I too careless? Was I close to the other side? What would happen if I
touched both electrodes with my finger?

Unless the phone rang, you'd come away with a "tickle", if that much. If
it rang at the moment you were touching, you'd get bit hard enough to
remember you don't wnt to do that again, but unles you're particualrly
sensitive to electrcitiy, not much more.

All bets are off if you try this experiment while a lightning storm is
in progress.

Usual "not ringing" voltage (AKA "Battery", in the parlance of
phone-folks) is about 48 volts DC. When a ring is actively in progress,
I've heard numbers ranging from 80 to 105 volts AC being called
"normal". During a conversation, 30-48 volts of modulated DC is typical.

 

[Tom Biasi]

">

Was I too careless? Was I close to the other side? What would happen if I
touched both electrodes with my finger?

Don already answered the technical part of your question, I'll respond to
the safety part.
Yes, you were too careless. You admitted you didn't know what voltage was
present and you went ahead and touched the wires anyway.
This time no problem. Clean up you habits.
Regards,
Tom

 

[John Larkin]

Was I too careless?

No. Telephones are "low voltage" wiring, like doorbells and fire
alarms, and are not dangerous. Dangerous voltages are wired
differently and are subject to licensing, inspection, and and building
codes.


John

 

[DecaturTxCowboy]

Was I too careless? Was I close to the other side? What would happen if I
touched both electrodes with my finger?

Ever watch an outside plant lineman repair a buried splice in the rain
standing or sitting on damp earth? You'll notice we don't take any
special precautions. At most, the 48 volt line current will tickle, but
the reflex action when you get across the 90 VAC ring current could
cause you to fall off a ladder.

Replace the word current with voltage. For some weird reason, the telco
industry calls voltage "current" and alternating current power as "battery".

A or signal battery = 24 VDC un-filtered (has hum) for relays and buzzers
B or talk battery = 24 VDC filtered (has no hum)for intercom
Ring current = 90 VAC or 105 VAC ringing voltage
Lamp battery = 16 VAC
Foreign battery = any outside power leaking into the circuit, like an AC
line.

 

[Don Bowey]

Ever watch an outside plant lineman repair a buried splice in the rain
standing or sitting on damp earth? You'll notice we don't take any
special precautions. At most, the 48 volt line current will tickle, but
the reflex action when you get across the 90 VAC ring current could
cause you to fall off a ladder.

Replace the word current with voltage. For some weird reason, the telco
industry calls voltage "current" and alternating current power as "battery".

A or signal battery = 24 VDC un-filtered (has hum) for relays and buzzers
B or talk battery = 24 VDC filtered (has no hum)for intercom
Ring current = 90 VAC or 105 VAC ringing voltage
Lamp battery = 16 VAC
Foreign battery = any outside power leaking into the circuit, like an AC
line.

Only a complete novice in the telco world (or maybe a lineman) would call
"AC " a battery. I spent a few years in the industry and NOBODY ever said
such a stupid thing.

On a wet day we NEVER worked on a line without rubber gloves.

Don

 

[DecaturTxCowboy]

Only a complete novice in the telco world (or maybe a lineman) would call
"AC " a battery. I spent a few years in the industry and NOBODY ever said
such a stupid thing.

Ummm...mebbe after a few years and then 20 more you might have heard of
it. Just a guess.

Look at the schematic of a IA2 key system, you'll see a reference to
"lamp battery" which is 16 VAC power.

 

[Don Bowey]

Ummm...mebbe after a few years and then 20 more you might have heard of
it. Just a guess.

Look at the schematic of a IA2 key system, you'll see a reference to
"lamp battery" which is 16 VAC power.

Well, if you need to pick nits....... My NCS date is in 1955, so I guess my
reference to "a few years" was a little off.

Do you realize that the Lamp Battery lead was originally connected to a DC
supply? Connecting it to an AC supply doesn't validate your idea that they
ever called AC a battery.

Don

 

[Michael A. Terrell]

Well, if you need to pick nits....... My NCS date is in 1955, so I guess my
reference to "a few years" was a little off.

Do you realize that the Lamp Battery lead was originally connected to a DC
supply? Connecting it to an AC supply doesn't validate your idea that they
ever called AC a battery.

I saw an old 1A2 PBX still using banks of batteries in the '70s at
the Pontiac dealership in Middletown Ohio. It had a couple racks full
of two cell, 4 volt clear lead acid batteries. Ohio Bell no longer
wanted to service it, so they replaced it with one of the early japanese
electronic key systems. It was a real piece of crap. I never had any
problems with the telephone to page interface in the Western Electric
1A2 system, but in a years time four separate paging interfaces
exploded. They had the design too close to the limits, and lost a lot
of aluminum electrolytics every time there was a power surge, or a
nearby lightning strike. BTW, Ohio Bell abandoned the old system in
place, so I took most of the 4 volt batteries and used them around my
shop, for years. I also pulled out over 1000 feet of 25 pair cable when
I replace the wiring for their paging system. It made great pull wire,
since they ran from the upstairs equipment room, down to every place
that I needed to pull a new single pair cable.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Don Bowey]

I saw an old 1A2 PBX still using banks of batteries in the '70s at
the Pontiac dealership in Middletown Ohio. It had a couple racks full
of two cell, 4 volt clear lead acid batteries. Ohio Bell no longer
wanted to service it, so they replaced it with one of the early japanese
electronic key systems. It was a real piece of crap. I never had any
problems with the telephone to page interface in the Western Electric
1A2 system, but in a years time four separate paging interfaces
exploded. They had the design too close to the limits, and lost a lot
of aluminum electrolytics every time there was a power surge, or a
nearby lightning strike. BTW, Ohio Bell abandoned the old system in
place, so I took most of the 4 volt batteries and used them around my
shop, for years. I also pulled out over 1000 feet of 25 pair cable when
I replace the wiring for their paging system. It made great pull wire,
since they ran from the upstairs equipment room, down to every place
that I needed to pull a new single pair cable.

Sometimes I wonder why, but when I retired I kept my Key Systems Manuals,
Data Service Manuals, Interconnect Manuals, and my favorite Bell Labs
Records. Nostalgia isn't what it used to be, but........

 

[Michael A. Terrell]

Sometimes I wonder why, but when I retired I kept my Key Systems Manuals,
Data Service Manuals, Interconnect Manuals, and my favorite Bell Labs
Records. Nostalgia isn't what it used to be, but........

I have some Stromberg-Carlson 1A2 manuals. I maintained them for
some AM radio stations, the last one was replace four years ago. I
still have a couple new 1A2 line cards and interrupters, somewhere,
along with about 1000 good used telephone slide lamps for the old
phones. I have a few of the older, larger version used in switchboards.
They have wood wedges for bases.
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[DecaturTxCowboy]

Connecting it to an AC supply doesn't validate your idea that they
ever called AC a battery.

That's not my idea, but if you read the manual to any 1A2 key system
*IT* will validate my statement when you see a reference to the "lamp
battery" being fed from the 16 volts AC power.