Illegal free calls from old public phones
Free telephone calls were appealing in the past when calls were expensive in real terms with the only phones available were the old-style dial type. This page starts with the ways to make free calls - all illegal - that were used by ordinary people without specialist equipment, all brought to life with recollections from people who were there at the time. The page goes on to what could be achieved - still illegally - with specialist equipment. Today’s digital systems have made these methods redundant as free calls can now be made legally to all over the world.
By the webmaster: her teenage recollections with further research and contributions from others who lived at the time
The principle behind making free illegal calls
The procedure behind making a free call on a dial phone was to mimic the clicks that came from dialling to the number that one wanted, ie one click for one, two clicks to two etc. There were several ways to do this as described below.
The procedure worked for all dial phones, both public phones and housephones, but I only knew it done from public phones. Free calls were illegal and a clear get-away route was essential to prevent being caught. Normally only older children and teenagers took the risks. I don't think they regarded it as stealing.
Simple free calls: tapping the cradle
Clicks to mimic dialling clicks could be made fairly easily by jogging the cradle up and down fairly rapidly at the same rate as dialling. This was easier said than done, but it was possible to become quite proficient at it.
Example from the 1950s
In the 1950s when I was a teenager - and possibly as early as the 1930s and 1940s, I knew fellow-teenagers who did it, and I knew how to do it myself although I never dared to do it. I thought that if I did, a police car would come roaring round the corner, sirens screaming and cart me off to a police station. As far as I know, though, on-one was ever caught.
Example from the 1960s
When I was a student in the 1960s in Brighton I was with a guy in a phone box when he called every cinema in town (probably about six) to ask what film was on and what time the shows started. All the calls were free. He achieved this by successfully tapping the numbers out on the receiver rest (cradle). He only made one mistake and got the wrong number, but he managed to get the right number on his second attempt.
Example from the 1980s
I know for a fact that tapping the cradle to make free calls in phone boxes was still possible as late as the early 1980s in Scotland, but I can't speak for elsewhere.
My friend's parents put a lock on their housephone which stopped the dial from turning. They didn't know that we could still make calls by tapping out the number. This was long before the days of itemised billing, of course.
The worst offenders
When I worked for the Plessey company in Liverpool which made telephone exchanges, those in the know told me that the worst offenders for making free calls were the policemen on the beat. They were given an allowance of 2 pennies (tuppence) to make check in calls to the station, but they kept the money and tapped out the number on the cradle. They were experts at it.
[I understand that the police could use the phones in police boxes free, but presumably there were fewer of them around.]
This guy showed me another way to make free calls, by what was called back dialling: Turning the dial all the way round and allowing it to run back to what I think was nine minus the number - or it could have been ten.
Another trick for free calls which did take a bit of setting up was to make a reverse charge call from one phone box to the other via the operator - all done with false names of course. At that time the operators couldn't tell if they were calling a phone box or a private number.
Cheap calls exploiting the person-to-person facility
At one of the places I lived as a student, the landlord had installed a coin box phone in the hall for the students to use. He worked for the post office so there was never any question of our trying to get free calls with him prowling around. On one occasion, though, we did get exceptional value for our money, albeit with a waste of our time: We made a person to person call from this phone to a student friend in a London Hall of Residence. They took over an hour to find him and bring him to the phone, but in the end the call cost just a few pence because it was only charged from when he came to the phone and confirmed his name.
Free calls with specialist equipment
All the methods for the illegal free calls described above were available to ordinary people. There were, though, other methods for those who knew a special code or trick to bypass the exchange, or had access to a device that could generate the sounds that mimicked the dialing clicks or had access to specialist equipment. The methods were illegal and risky, as they could be detected by the telephone company or law enforcement.
Specialist equipment to enable free calls
• Blue boxes: These were electronic devices that could produce the tones used by telephone companies to control long-distance calls. By using a blue box, one could dial an operator, play a certain tone to seize the trunk line, and then dial the desired number for free. Blue boxes were popular among hackers and phreakers (phone hackers) in the 1960s and 1970s, and some famous users included Steve Jobs and Steve Wozniak, the founders of Apple.
• Black boxes: These were devices that could trick the telephone exchange into thinking that a call was not answered, and thus not charge for it. A black box would answer an incoming call, but keep the line open without sending a signal to the exchange. The caller and the receiver could then talk for free until one of them hung up.
• Red boxes: These were devices that could simulate the sounds of coins being deposited into payphones. By using a red box, one could make free calls from payphones by playing the appropriate tones for each coin.
• Loop lines: These were pairs of phone numbers that were connected internally by the telephone company for testing purposes. By dialing one number and then quickly dialing another, one could create a loop that allowed two parties to talk for free. Loop lines were often discovered by phreakers who scanned the phone network for them.
The end of risky illegal free phone calls
The above methods became obsolete as technology advanced and telephone systems switched from analogue to digital. Today completely free calls are readily avaiable thanks to apps like Skype, WhatsApp and Facebook Messenger. What's more, they are video so that people can see one another as they talk.