This was drawn from the actual PC board of the telephone set. It was a cheap throwaway type telephone from long ago. Some of the part labels couldn’t be seen without removing the part. We will probably have a difficult time convincing the young kids that telephone sets had a cable that had to be
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Here’s a pic of a TP3051J telephone interface chip (CODEC and Filter). Yes, a picture of the actual chip inside of the IC, after I popped the top off of it. I have a lot of them so I figured that checking one out to see what was in it would be fun. The pic
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The guy at our computer club let me take a picture of his Sonim cell phone. These are advertised as indestructible, and they show Youtube videos of them abusing it as a ball, and a truck running over the phone. The finally killed it with a bullet.
I took these pictures at the Orange County Sheriffs Training Academy located on the site of the Tustin Marine Corps Air Station, near the huge blimp hangars. This seems to be a new addition to their ‘museum’ collection, which includes such things as weapons and improvised explosive devices such as the often seen alarm clock
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This circuit is connected across the phone line, and the pushbutton switch is placed close to the phone. When the pushbutton is pressed, the red LED lights up. The circuit is polarity sensitive so if the LED does not light, then the connections may have to be reversed. Once the LED is lit, the phone
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I was perusing this circuit on Redcircuits.com when I noticed the capacitor C4 seemed to be backwards – the plus should be on the left. I contacted the author and he said that he would correct it. The idea of talking and listening at the same time “full duplex”, which is technically a communications term,
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The Antique Telephone Collectors Association annual show took place yesterday at Placentia Presbyterian Church, Placentia CA. I got a few good pics of the stuff. Those blue and white roundish “Public Telephone” signs are selling for $500 to $1000 apiece. Just think of all the money one could make if they had collected a bunch
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I blogged this a long time ago, but my old blog is gone, so here it is again. I unsoldered a large number of these 600 ohm hybrid transformers from PBX boards. Each transformer has four 600 ohm windings, and is used to interface to the PSTN (telephone central office). Notice that there is a
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This Instructable tells how to build a LED flashlight that is connected to and derives its power from the telephone line. If you can’t take the time to read this, at least read the conclusion at the end. First off, I must warn the reader that this is illegal, foolish, dangerous and can cause problems
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