Saturday, 7 November 2015
Free phone calls
In the 1960s I knew nothing about Apple, Wozniak, Jobs, or Blue Boxes, but I was in a boarding-school and did occasionally need to phone home. Stuck below the staircase of the main building of Woolverstone Hall was a public phone booth. It contained the old-fashioned black coin-operated typical UK public phone of the time, with its A and B buttons and its heavy bakelite telephone handset that sat upon a rotary dial. (The photo here shows a similar sort of setup, though not the actual equipment at school.) It cost a lot of money to phone to London, where my mother lived, so I seldom used the phone. However, an event occurred that meant that I needed to phone fairly regularly, and that was just too expensive, so somehow I figured out that phoning could be done for free.
Looking at the Blue Box video and remembering how I solved my own problem, I think that the UK phone system at the time was very different to that of the US. The latter was already digital and relied on tones to form its connections, whereas the UK system was still analogue and used pulses to generate the necessary dialling information. I suppose I must have heard from someone that it was possible to generate these pulses through the use of a cunning trick, so I experimented a bit and it wasn’t long before I had mastered the technique and could call anywhere that didn’t require the intervention of an operator.
The trick was to tap out the required number with the handset cradle, with a brief pause between each digit of the number: one tap for 1; two taps for 2; three taps for 3…10 taps for 0. The timing between taps was crucial, as there really could be no delay: a brief delay in fact signalled the end of one digit and the start of the next.
In those days, telephone “numbers” were more often than not formed by the name of an exchange and a unique number, so to phone home I had to dial the “number” Woolwich 5869. In telephone terms that was WOO5869 and the WOO had to be translated into digits. That was easy enough, however, as the telephone dial provided both alphabetic and numeric data.
nine taps pause six taps pause six taps pause five taps pause eight taps pause six taps pause nine taps pause
And it worked!