This Free Phone Call Device Caused Chaos For BT!

in the usa we didnt even need electronics, we just needed a box of captain crunch cereal, came with a nice 2600 hz whistle :D

Not really related but another public phone thing - back in the 70's/80's small kids used to shove crisp bags up the coin return. Adults couldn't reach them. A few days later you'd go back and pull the bag out and the change would rain out. Then over to the sweet shop on the other side of the car park to spend it. Fun times.

I was a BT exchange engineer and remember this very clearly. I worked in an electronic TXE4(RD) exchange. These had DTMF receivers fitted to the registers, initially just a few, but later on they were fully provided and most lines were set to dual signalling by default. On this particular exchange type all data was held by way of wires threaded through ferrite core transformers. So I had to re-thread every single public and renters coinbox line on the exchange to only accept pulse dialling. The coinbox engineers modified the payphones for pulse dialing. The later TXE4(A) exchanges had a VDU terminal and only needed a couple of commands typed in. Linkwise with digital exchanges. I think I got a few Saturdays overtime out of it.

The analog of this in the US was the "blue box" created by John Draper, a.k.a. Cap'n Crunch. It worked exactly like the Tandy dialer shown, except the MF switching frequencies were different from American DTMF dialing digits. It also included two additional buttons to create the "KP" and "ST" tones required at the start end end of the dialing sequence. The Tandy DTMF dialers were easily converted to blue box MF dialers by switching the crystal. IIRC the DTMF dialers used 3.58MHz stock and changing that out to 6.5536MHz turned it into an MF dialer. My guess at the remedy installed is they just added a LC notch filter at 2400 or 2600Hz to the handset microphone. We also had "red box" coin simulators that produced bursts of 1700Hz + 2200Hz which counted as 5 cents each. A 25 cent coin generated 5 quick bursts. The capital to start Apple Computer came from selling a VW van, and HP calculator, and 50 blue boxes.

I'm glad you didn't appear on film again. It's too distracting you being so dead sexy and all, i could scarcely pay attention to the content. I hope you learned your lesson about not pirating french radio.

Phone Phreaking, those were the days. Was a pretty big oversight that it's amazing is wasn't sorted way before it was.

I hacked the BT pulse dial system in 1969. Free calls using switching codes. In the 80s I was using a dial up modem to access the Internet through a tech support line at Manchester Uni. Free access to anywhere in the world, including NASA and JPL. Happy days.

My dad worked for Bellsouth Security here in the states and his job was to assist in tracing and tracking phreakers. He helped put away quite a few of them in the 80s. I recall him being mentioned in a couple of books we used to have on the shelf at home but I don’t recall their titles. I do recall him mentioning one guy getting paroled after a lot of years and he started keeping a revolver in his nightstand in case someone came knocking. They never did. I think he was being a bit overcautious in that regard. I never got the impression most phreakers were violent, just skilled opportunists who enjoyed gaming the system. Anyway, he had lots of stories growing up.

When I was in the Air Force, we would have to live on base for a week at a time to pull alert (quick response to Cold War threats). The phones in our rooms were push button, but the buttons just activated pulse dialing, which worked unless you wanted to call long distance with your long distance calling card (remember those days) where you had to enter your calling card number as well as the phone number you were calling. This required DTMF tones. I bought one of the Tandy dialers and plugged the 12 (or was it 16?) digit calling card number and the phone number into the memories. Worked like a champ.

Jobs and Woz made these back in 1975, pre-Apple computer

In 1980 I know of a certain broadcast engineering training centre (just outside Evesham!) where one of the engineering students (previously of BT) modified a loop-disconnect phone box. If you didn't know, it operated normally, but if you knew the trick dialling 1 gave you 5p worth of calls; 2, 10p; 3, 15p etc. - at least that's how I remember it working. So there was always some change in the box, but never enough to cover the calls! It took a BT engineer to make a special visit to strip it down and see that some naughty chap had modified it so the dial pulses fed into the coin-counting mechanism...!

Here in the states we called modified tone dialers a 'Red Box'. Replace the crystal inside the tone generator with a colorburst crystal from a television set. Advanced designs would include a mercury tilt switch that would allow the tone dollar to work normally as they were sold for and if you flipped the dialer upside down it would become a Red box The emulated the tones used when you inserted coins into payphones, to fool live operators who listened for the coin tones.

On another note, the dialers shown, could bypass hotel phone billing systems on old electromechanical PBX's if their outgoing trunks, which where technically lines, supported DTMF. You would dial a digit to access a local trunk, in the US it was usually 9 and 8 was for long distance, and the use your dialer to send the digits to the trunk. The hotel billing system was looking for dial pulses.

I remember international calls in the 90s being extremely expensive.

who remembers resting a BT phone card with some nail varnish or the BT Cellnet phones you could turn off and on the pay as you go credit would re-load

In Canada, you didn't need any special equipment. You could call collect to any pay telephone and have someone answer and accept the charges. The telephone company had to eat these long distance toll charges.

I used stick foil on 10p pieces to make them appear as 50p pieces to BT phones. 1989.

We had a ancient phone box that still had a rotary dial all the way up until the box was removed completely in the early 2000s. As a young teen I read how if toggled the phone hook just right you could make a fre call. To my amazement it worked, I think on the third time I tried it a police car happened to come around the corner and I was terrified they somehow knew what I was doing and never did it again 😂. Sorry BT, I owe you 30p,

Reminds me of the anarchists cookbook era lmao

Well, that’s set me tone of conversation. 🤣