Re: telephone cable voltage

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Re: telephone cable voltage

There is around 50 volts DC on the line when the phone is on the hook.
When off the hook there is about 10 volts DC.
When ringing or dial there is a high voltage AC signal on the line.
 
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Re: telephone cable voltage

you are absolutely right
 

Re: telephone cable voltage

I suggest reading book/ebook "Understanding Telephone Electronics" by Stephen J. Bigelow, Joseph J. Carr, Steve Winder - Fourth Edition.

;-)
 

Re: telephone cable voltage

Just adding to the basic question, there is CLI data during in the start of ring signal. And you can hook up some white LEDs connected in series to the telephone line for a free of charge night lamp, without putting line on hold.

 

Re: telephone cable voltage

I dont suggest any additional load on phone line, specially if is modern digital telephone centrale. Self monitoring and diagnostics system can automaticlly disconnect phone line until further notice, and wait intervention of telecom service personnel.

I know that earlier people charge batteries, power car bulb 21W to light room,... and other similar things, but I think that phone line should stay only for that purpose.

Telecom request on phone line to use only certified devices.



I also use my various DIY devices on phone lines on longer period without problems, but caution does not hurt.
 

Re: telephone cable voltage

I'm sorry to say that the original post was not a request for help but intended to reply in an old thread (dated 2004!) https://www.edaboard.com/threads/22907/#post1187642

- - - Updated - - -

And having just opened the link that FvM has posted I see that he already found that thread
 

Re: telephone cable voltage

gelled01 said:
When ringing or **broken link removed** there is a high voltage AC signal on the line.
Click to expand...
Yes, I learned that the hard way as a youngster, fooling around with the wiring when the phone rang - quite a shocking experience!8-O

('scuse the bad pun. )

- - - Updated - - -

Hang on - why is there a link to an advert on the word "dial" in the first post - is this just spam?
 

Re: telephone cable voltage

godfreyl said:
Hang on - why is there a link to an advert on the word "dial" in the first post - is this just spam?
Click to expand...

Good catch, I'll edit the post and delete the post in the other thread.
Everybody, say byeeeee to the OP :lol:
 

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