Telephone call charge rates: 3-minute history

[brenellic2000]

Many wrist-watch chronographs between 1940s-1970s had pronounced 3, 6 and 9 minute markers on their cumulative minute register. These are documented and widely accepted as being for observing telephone call-rate charge bands. (These also help in dead reckoning navigation: etc 3-min = 1/20th hour; 6-min 1/10th... but 9-min?).

Smiths also made in the 1960s clockwork table-top telephone timers calibrated at different call rates. These and the wrist-watch markers became largely redundant after STD.

Other countries also adopted the initial 3-min charge rate (1 or 3-min increments thereafter) but when and why was 3-mins chosen as the international standard, and not 2, 4 or 5-minutes? As these markers do not seem to appear on pre-WW.II timepieces, were they a result of the war time necessity to ration calls due to damaged lines/networks?

Barry

The cynic in me says it was chosen because it is difficult to judge three minutes, a second over and another chunk on the bill. A quick google has "the average 'phone call lasts 3 minutes 15 seconds".

[paulsherwin]

The calls would have originally been timed and charged by an operator. Presumably charging in increments shorter than 3 minutes was impractical.

[emeritus]

Immortalised in the chorus of the song "Sylvia's Mother": ' And the operator said it's 30 cents more for the next three minutes'.

[brenellic2000]

All valid observations, but they don't solve they mystery!

[brenellic2000]

Hmmm... the 3-min rate was certainly in use in 1900 for trunk calls (outside the local exchange on a mileage rate). A maximum of two consecutive 3-min call were permitted. That explains the 3- and 6-min markers but not the 9-min!

Did the local exchange have a built in automatic clock, or did the operator rely on a wall clock?

[Vintage Engr]

Originally Posted by paulsherwin

The calls would have originally been timed and charged by an operator. Presumably charging in increments shorter than 3 minutes was impractical.

And then the operator would interject " Would you like to place another 4d in the slot, or hang up?"
This happened so many times when calling my girlfriend!
We didn't have a 'phone at home..

David.

[terrybull]

I suppose it could be to keep track of the 3 minute blocks of call times if you want to make a longer call. Not to go into another 3 minute charge period.
https://youtu.be/KoKSOhzL8VY

[G6Tanuki]

I remember an early LED digital-watch which had a "call-minder" function which would beep after something like 2 minutes 45 seconds for those who were paranoid about call-costs.

[GlenTyan]

My initial thoughts on this was that three minutes was adjudged to be the longest time a man could speak to his wife on the phone without an argument. However, on thinking back to the sixties and my fading memories of Master Wall clocks both in large manual centres the clocks had a one minute pulse to advance the wall clocks but how that one minute pulse became three on a manual board I'll need to leave to others, however when Strowger came along we got S & Z pulses derived from the Master wall clock if I remember correctly and as Strowger systems got exported round the world so did the three minute timer. It may well be the three minute time originally being arbitrary derived as a call charging period just became the international default. Perhaps this will jog the memory of others and how metering pulses were derived. For Director GSC's a Tariff Pulse Machine derived a short interval pulse and the controlling relay set had a divide by so many relay setup counter to send the metering signal back to the director exchange. I can still see the kit as clear as day but the finer workings are fading. Feel free to add to or correct me.

[mole42uk]

Originally Posted by emeritus

Immortalised in the chorus of the song "Sylvia's Mother": ' And the operator said it's 30 cents more for the next three minutes'.

Inflation strikes - the lyrics say “40 cents more…..”

[emeritus]

Imperfect recollection: I don't think I have heard it since the 1970's!

[mole42uk]

Originally Posted by emeritus

Imperfect recollection: I don't think I have heard it since the 1970's!

It was a very popular song when I used to service juke boxes and your mention of the title brought it straight back into my head - these days they call it an earworm!

[Welsh Anorak]

Inflation again - many landline networks with inclusive minutes are free for the first hour, then charge, so you are encouraged to hang up and redial should you need to.
Not too much use when you are listening to music interspersed with 'your call is important to us'...

[Pellseinydd]

Originally Posted by GlenTyan

My initial thoughts on this was that three minutes was adjudged to be the longest time a man could speak to his wife on the phone without an argument. However, on thinking back to the sixties and my fading memories of Master Wall clocks both in large manual centres the clocks had a one minute pulse to advance the wall clocks but how that one minute pulse became three on a manual board I'll need to leave to others, however when Strowger came along we got S & Z pulses derived from the Master wall clock if I remember correctly and as Strowger systems got exported round the world so did the three minute timer. It may well be the three minute time originally being arbitrary derived as a call charging period just became the international default. Perhaps this will jog the memory of others and how metering pulses were derived. For Director GSC's a Tariff Pulse Machine derived a short interval pulse and the controlling relay set had a divide by so many relay setup counter to send the metering signal back to the director exchange. I can still see the kit as clear as day but the finer workings are fading. Feel free to add to or correct me.

The '3 minute' time interval was around long before Strowger - see attached from the 1891 London directory.
Calls were timed by the operator using clocks mounted above the switchboard. Some were just 'clockwork' clocks as per the GPO's 'Clock No 1' commonly found above small manual board.
The first timing clock was to my knowledge, the 'Clock 44' fitted in cord circuits with versions for different switchboards such as CB and CBS. See attached pictures of Clocks 44 on one of my CBS2 Switchboards.
The Clocks 46 were driven by pulses from a 'Clock 46' which gave 30 second pulses plus a series of pulses to give the 'three minute' pips on calls which were timed - switching to the left timed 'ordinary' calls and to the right for 'coin collecting box' calls. Only trunk calls prior to the introduction of Subscriber Trunk Dialling were timed. See attached page from the Vocabulary of Engineering Stores (1956) which describes the Clocks 44 and Clock 46. Clocks 46 were only fitted at exchanges with a manual board fitted with Clocks 44 - hence a lot rarer than the normal tall 'Clock 36' master clocks.

[brenellic2000]

Thanks. Perhaps 3-mins was simply chosen arbitrarily as a standard call... but why limit international trunk calls to a maximum of two consecutive 3-min calls? Line capacity?

[emeritus]

The limited number of international circuits could have been a factor. I remember my aunt getting a phone in the late 1950's and making a call to her sister-in-law in the USA when we were at her house on Christmas Day. The 3 minute call had had to be booked months in advance and had cost £4 for three minutes, which I think was about 2 days' basic wages for a manual worker at the time.

[Oldcodger]

International circuits. Prior to 1961 the only Transatlantic speech circuits were ( at first the 4khz system ) with 36 channels ,one of which was telegraph, with the 35 later being increased by narrowing the band to 3khz.
Local cal timing- honestly I cannot remember, but I seem to remember the operator writing the time of the start of a call on the ticket. Not something an apprentice noticed in the switchroom, even less so when calling my girlfriend from home resulted in me being put through to the trunk centre. I suspect no ticket was ever made for my calls.
Something I have not seen mentioned is the charge areas. Calls between adjacent areas were charged at local call rate, but calls passing through another area were deemed to be trunk calls. I often wonder if this created a situation of an intermediately area between large towns . Coventry and Birmingham comes to mind.

[Aub]

Originally Posted by emeritus

Imperfect recollection: I don't think I have heard it since the 1970's!

You're lucky 😄

Aub

[Pellseinydd]

Originally Posted by Oldcodger

International circuits. Prior to 1961 the only Transatlantic speech circuits were ( at first the 4khz system ) with 36 channels ,one of which was telegraph, with the 35 later being increased by narrowing the band to 3khz.
Local cal timing- honestly I cannot remember, but I seem to remember the operator writing the time of the start of a call on the ticket. Not something an apprentice noticed in the switchroom, even less so when calling my girlfriend from home resulted in me being put through to the trunk centre. I suspect no ticket was ever made for my calls.
Something I have not seen mentioned is the charge areas. Calls between adjacent areas were charged at local call rate, but calls passing through another area were deemed to be trunk calls. I often wonder if this created a situation of an intermediately area between large towns . Coventry and Birmingham comes to mind.

Prior to the introduction of STD on an exchange, local calls from an exchange were based on the 'unit fee' system' . The charge was based not by exchange areas but by the direct distance (as the crow flies!) between the two exchanges - one unit for up to 5 miles, 2 units for 5 to 7.5 miles, 3 units for 7.5 miles to 12.5 miles and 4 units for 12.5 miles up to 15 miles. Small rural UAX exchanges had 'multi-metering' junction relay sets which applied the relevant number of pulses based on the initial few digits dialled. Local calls pre-STD were untimed - just the relevant number of meter pulses when the called number answered. It was a bring job strapping up the relay sets - I just saw the end of the Multi-metering era when I joined in the late 1950's.

Over 15 miles were 'trunk calls' again charged by distance - distance/charges from main exchanges were sometimes shown on the telephone directory. Trunk calls were via the operator and by post WW2, most manual exchanges had the Clocks 44. The operator would write the ticket out - reset the Clock 44 then start it by turning to left if an ordinary sub or to the right if a coinbox rate subscriber. If the time was running out, she would intercept the call when the red light came on on the cord circuit by the Clock 44 and ask if they wanted more time nd if a coinbox they would be asked for more money.

Once STD appeared, 'multi-metering' was dropped and a 'local call' (still untimed) was for calls up to approx 15 miles within what became 'Charge Groups' with STD. The 15 miles was from the main Group Switching Centre' to the one in the next group. Hence in some rural area, you could get quite a distance for a local call. A local calls was to an exchange in your own group or an adjacent group. There were exceptions where GSCs were a long way apart. Then as STD rolled out the same system applied but with calls timed.

Interestingly, Birmingham Director Area Dialling Code Cards for 1959 and 1960 show a local code for Coventry - 'CO' (or 20) in 1960 and 1961 and for five figure numbers in 1959. For four figure numbers in 1959, the code was 'CO 3'. So all isn't as you would think! However as STD came in, they ceased to have a local code and it went into the 'a' zone of STD call charges.