atcomsystems.ca/forum Forums General General Telephone & Systems Information Call blocking circuit

Hello

I need a litte help.

Iam an installer of Voice and Data lines, and recently an installer of tel switches.

My question is concerning call blocking circuits using zener diodes.
I beleive I know the basics but would like to know how the circuit is built and how it works.

Thanks
Wes

Do you mean line sharing circuit? Only reason I ask is because I seen zener diode in your post.

Might be a useful place for you to start

https://www.hut.fi/Misc/Electronics/circuits/teleinterface.html

What actually do you mean by call blocking? Call blocking is normally done in the CO to prevent calls comming to your line. Do you mean call exclusion? Which is with multiple extensions when one is in use it can cut all the other ones off so they cant cut in to your converstaion.

------------------

Yes call exclusion is correct. A customer has asked me to put one a particular line that is tied to a modem and does not want anyone barging into the data transfer. I will replace with one the company will purchase but I was wanting to build one for further applications.

Wes

Try this, cheap and easy, Viking Electronics exclusion device, I've used them and they work.
https://www.vikingtelecomsolutions....B5L5S9F8H4MLJ21HK1HUMSP3UVE&PID=1209

That's a long address, just do a google on viking electronics.
mark

Does any one know what the tg-1 really is? I have had a lot of people look at them and say its a zener diode but there is no numbers to cross reference. I use to get something similar out of a place in NY several years back ,but they were blue ice cubed shaped with a pair of wires coming out. I guess who ever designed these did not want anyone to know what they were made of so they were molded in some type of epoxy in an ice tray.I was unsuccessful with my atempt to crack them open. Most techs would say what the heck are all theses blue ice cubes hooked to. looked real stupid hanging off the 66 blocks. They worked great but I prefer the tg-1's. I usually scotchlock one side then punch the other end of the tg-1 directly on a 66-110 block. But the most simple is to just get the exclusion line cord from viking for each device. I tryed several times to make my own, which somewhat worked.

[This message has been edited by clgjr (edited January 30, 2005).]

I have an old one I saved out of a system I was replacing about 8 years ago and some of the wires have fallen off of it, and now I wouldnt know where they connected to anyways but the z diode is labeled
a symble U
TDD S
89K A

Its hard to read it but it is laid out like that I dont know what the symbol says or maybe its just a picture. And there were some resistors connected to this also.
These things were always sort of a micky mouse type of wiring job especially if the wires fell off the 66 blks. You should do it properly so the next guy comming along can trace it out without things falling off. I would never use these things rather one made by DEEs it came in a module with all the terminals marked so you cannot go wrong with it.

------------------

mike sandman's gotem too.(sandman.com)
m