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Wireless telephones


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Hi Walid,
Here, http://electronics.howstuffworks.com/cordless-telephone.htm
is a pretty good explanation of the history of cordless phones in America. There are many different ways of modulation over the years and I think they are wrong about the 1st cordless phones: My 1st cordless phone used FM for the handset to transmit to the base at 27MHz, and AM for the other direction at about 1.8MHz. The handset had an AM radio's loopstick antenna in it for it to receive.

It stopped working and I didn't have a clue what was wrong. I simply guessed that the quartz crystal in the handset was broken, went to the manufacturer to purchase one and it worked! I think the crystal cost 2 bucks. I mounted the new one in rubber and it worked fine for years until I got tired of interference from other ones in my neighbourhood. Now I use one that is digital at 900MHz. ;D

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  • 1 month later...

This site is good but not excllent, I see it befor, it provide a surface info.
I want info enable me to identifiy the TX and Rx sections and isolating them and using them say as a walki-talki, or eabling me to make a hand set of different device see another main one, like this.......
I hear about some people i mt city doing this, what the amazing thing is that those people are out of electronics field at all, what they do? I don't know. How they learn this!!!!

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