Phone Phreaking

[Michael GilliganParticipant @michaelgilligan61133]

I have a distant memory of reading a good article about this in one of the ‘Sunday Supplements’

Some of the forum’s telephone engineers might like to elaborate

MichaelG.

.

 

[Hugh Stewart-Smith 1Participant @hughstewart-smith1]

Whoa! That takes me back to the mid-60’s when we found a way of getting free calls from ‘phone boxes.

By tapping out the number on the bar on the telephone cradle you could get connected for free. You had to tap the number with a pause between numbers and the numbers ‘0’ and ‘9’ could be dialled.

Does that ring any bells? – although it used to ring a few numbers!

We didn’t think ourselves as ‘phreaks’ though.

Hugh                                                                                                      Amadeal Ltd

[duncan webster 1Participant @duncanwebster1]

On the old dial phones which also had letters against the numbers, if you dialled GULO6 first, you got free calls from a phone box. Not that I ever did you understand

[John HaineParticipant @johnhaine32865]

Old phone boxes used to have a coin mech that generated 10pps “dial pulses” to indicate the coin type.  In order to discriminate between these and normal pulses the line was reversed in “quiescent” mode and series diodes used in the payphone to decide which of the dial or mech was in circuit.  Once a valid coin had been signalled the exchange would reverse the line back to normal to permit dialling and speech.  I knew of at least one payphone in a university hall of residence where enterprising engineers had shorted out the dial diode so the coin value could be “dialed in”.  Ah, those were the days before hacking became a thing.  I recall that Plessey had a “consulting vandal” they used to try to break payphones too.

[Robert Atkinson 2Participant @robertatkinson2]

When making calls from work most extensions would have international and premium numbers blocked. One way around that was to use the handset on the Fax machine…

[Author]

Posts