The first Blue Payphones

[Hermitcrab]

Good evening and for my first post here's a basic question. When the first electronic "Blue Payphones" were widely introduced around 1982 replacing those hideous grey (mostly) pay on answer phones, why was the minimum charge set at 8p instead of 5p (i.e. you would now have to insert 4 x 2p pieces). I would sometimes observe bewildered tourists struggling to understand why, when they inserted less than 4 x 2p pieces, the call didn't connect. I also remember a strongly worded letter in the press strongly complaining about this increase from 5p to 8p!

[Sparks]

Rough guess, 40p will divide by 5p, 8p and 10p. I haven't a clue otherwise! I remember if you finished your call with some 'coin credit' remaining you could press the 'Follow On Call' button and use your remaining credit.

[Hermitcrab]

I described the old pay-on-answer coinboxes as hideous because people quite visibly had a lot of trouble using them - quite often the coin when inserted would vanish into the coinbox while the pay tone kept going regardless. If you rang the operator he/she would usually connect your call if you explained that you had lost your 5p or 10p in this way.

Pay on answer boxes which took 50p pieces did exist, there were a couple at Victoria Station for example. Development of these was discontinued and the Blue Payphone took over.

[hamid_1]

That's an interesting question, one I asked myself at the time those 'new' payphones were introduced.

I can only assume that BT had a long-term plan to increase the minimum fee to 10p, which they did in the late 1980s. But in 1980 the minimum fee had only just been increased from 2p to 5p (more than double). All Pay-on-Answer coinboxes were converted to accept 5p and 10p coins.

I guess that in 1982, doubling the minimum fee again after only 2 years wouldn't have gone down well with the public, so perhaps BT opted for 8p as a compromise. As mentioned, the new payphones allowed the user to put unused credit towards another call - a form of appeasement for the price increase.

It's actually a bit surprising that those early electronic payphones were equipped with 2p, 10p and 50p coin slots when the minimum fee was already 5p. Perhaps those phones were already in development before the 5p minimum fee was introduced?

Those phones appeared to have been experimental. They weren't around for very long and were replaced by the BT Payphone 500 / 600 range, which had a single coin slot that accepted all sorts of coins. That design is basically the same as today's payphones.

BT withdrew the acceptance of 2p and 5p coins from their payphones in 1990 by which time the minimum fee was 10p. BT said at the time that 2p & 5p coins filled up the coinbox too fast. Coincidentally in 1990 a new smaller 5p coin was introduced. I can't accept their argument that the new miniature 5p would fill a coinbox very quickly, but presumably BT didn't consider it worth the trouble to convert all the coin mechanisms. Anyway since the 10p cash minimum fee was introduced, smaller coins had become almost obsolete. Also, Phonecard payphones had effectively been charging in 10p units since they were introduced some years earlier. Surprisingly in 1995 an Italian company called Interphone took over the former Mercurycard payphones and converted them to accept cash - including 5p coins - although the minimum fee was still 10p.

[Pellseinydd]

Originally Posted by hamid_1

<snip>

BT withdrew the acceptance of 2p and 5p coins from their payphones in 1990 by which time the minimum fee was 10p. BT said at the time that 2p & 5p coins filled up the coinbox too fast. Coincidentally in 1990 a new smaller 5p coin was introduced. I can't accept their argument that the new miniature 5p would fill a coinbox very quickly, but presumably BT didn't consider it worth the trouble to convert all the coin mechanisms. Anyway since the 10p cash minimum fee was introduced, smaller coins had become almost obsolete. Also, Phonecard payphones had effectively been charging in 10p units since they were introduced some years earlier. Surprisingly in 1995 an Italian company called Interphone took over the former Mercurycard payphones and converted them to accept cash - including 5p coins - although the minimum fee was still 10p.

I have a payphone that was still in public use on the BT network in a K6 kiosk until it was replaced in 1994 (by a later modern payphone) and it was set up to accept 5p (the old shilling size) and 10p (the old 'florin' size). Plus I've got a 'pre-decimal' GPO A/B box that was in use until 1992 ! It was replaced when the old 'florin' sized 10p piece was replaced by the smaller one! There are always exceptions

[electronicskip]

Originally Posted by hamid_1

That's an interesting question, one I asked myself at the time those 'new' payphones were introduced.

I can only assume that BT had a long-term plan to increase the minimum fee to 10p, which they did in the late 1980s. But in 1980 the minimum fee had only just been increased from 2p to 5p (more than double). All Pay-on-Answer coinboxes were converted to accept 5p and 10p coins.

I guess that in 1982, doubling the minimum fee again after only 2 years wouldn't have gone down well with the public, so perhaps BT opted for 8p as a compromise. As mentioned, the new payphones allowed the user to put unused credit towards another call - a form of appeasement for the price increase.

It's actually a bit surprising that those early electronic payphones were equipped with 2p, 10p and 50p coin slots when the minimum fee was already 5p. Perhaps those phones were already in development before the 5p minimum fee was introduced?

Those phones appeared to have been experimental. They weren't around for very long and were replaced by the BT Payphone 500 / 600 range, which had a single coin slot that accepted all sorts of coins. That design is basically the same as today's payphones.

BT withdrew the acceptance of 2p and 5p coins from their payphones in 1990 by which time the minimum fee was 10p. BT said at the time that 2p & 5p coins filled up the coinbox too fast. Coincidentally in 1990 a new smaller 5p coin was introduced. I can't accept their argument that the new miniature 5p would fill a coinbox very quickly, but presumably BT didn't consider it worth the trouble to convert all the coin mechanisms. Anyway since the 10p cash minimum fee was introduced, smaller coins had become almost obsolete. Also, Phonecard payphones had effectively been charging in 10p units since they were introduced some years earlier. Surprisingly in 1995 an Italian company called Interphone took over the former Mercurycard payphones and converted them to accept cash - including 5p coins - although the minimum fee was still 10p.

Mercury payphones were blue weren't they??

[hamid_1]

Yes, the Mercurycard phones were blue as well, but before they came along, BT introduced some electronic payphones with a blue follow-on-call button, and often a blue handset to match. These were referred to as "blue payphones".

There's one on display in Avoncroft Museum inside a red K8 kiosk - see attached photo - along with a blue Mercurycard kiosk visible behind.

There's also a website with some details of the BT CT22A blue payphone: http://payphone.illtyd.co.uk/ct22a-blue-payphone

The Avoncroft example as well as the one on the above webpage has a red LED display, but I remember seeing LCD versions (black digits on a grey background). However as I said, the CT22A design was soon replaced altogether by the Payphone 600 later in the 1980s. After decades of service from the A-B and pay-on-answer payphones, the 1980s were a period of rapid technological change.

And yes, I also heard about a pre-decimal A-B coinbox still in use for years - wasn't it on a remote Scottish island? Did the locals have a special supply of old coins to use in it, or did it also use 1 and 2 shilling coins? Shillings and florins were identical in size and value to the decimal 5p and 10p coins and were therefore interchangeable until the 1990s when they and the old 5p and 10p coins were withdrawn. I presume that's what necessitated the replacement of the box. I'm sure I've seen decimal A-B boxes too (2p & 10p).

[Pellseinydd]

Originally Posted by hamid_1

<snip>
After decades of service from the A-B and pay-on-answer payphones, the 1980s were a period of rapid technological change.

And yes, I also heard about a pre-decimal A-B coinbox still in use for years - wasn't it on a remote Scottish island? Did the locals have a special supply of old coins to use in it, or did it also use 1 and 2 shilling coins? Shillings and florins were identical in size and value to the decimal 5p and 10p coins and were therefore interchangeable until the 1990s when they and the old 5p and 10p coins were withdrawn. I presume that's what necessitated the replacement of the box. I'm sure I've seen decimal A-B boxes too (2p & 10p).

The 'pre-decimal' A/B box was one of three fitted on the cruise liner Canberra - The slots from the front were 2/- (old florin or first version of 10p), 6d and 1/- . Could also be used in Australian and New Zealand ports where they used 5 cent, 10 cent & 20 cent coins with the 20 cent being the front slot. Hence the three survived in use when the Canberra was in port in the UK/Australia/New Zealand until the introduction of the UK's smaller 10p piece.

The A/B box that was in use until 1994 had a 5p (old shilling) slot at the front and a 10p (florin/two shilling) at the rear. There was a stock of coins kept on the island - it was emptied by the local sub-postmaster/part-time BT engineer, Shetland pony farmer, part-time fireman etc He just recycled the coins in the box! It was on the UK's most remote inhabited island!

I've never seen another 5p/10p A/B box. All the PO ones were converted from penny/sixpence/shilling to 2p/10p. Sadly the 2p/10p boxes will not work with the modern 2p piece since they became copper plated steel in the 1990's as they are thicker. Luckily I have quite a stock of the old bronze ones (bronze in them is apparently worth more than 2p! Otherwise you have to modify the 2p slot.

Any with three decimal slots - 5p(at front); 1p or 10p in middle and 2p at rear are from the Irish 'Telecom Eireann' converted ones - some having been sold to them by the GPO in early days of STD.

[Hermitcrab]

Originally Posted by hamid_1

The Avoncroft example as well as the one on the above webpage has a red LED display, but I remember seeing LCD versions (black digits on a grey background).

The payphones with the red LED display were the trial version installed at a few locations throughout the country such as Trafalgar Square, Paddington Station and a couple I saw in Leeds city centre etc, in dribs and drabs from about 1980 to 1982.

In 1982 BT decided the trial was successful and ordered several thousand units, these being the second version with some improvements which included the change to a black LCD display. To most people though the 2 versions would have looked much the same.

[hamid_1]

Originally Posted by Pellseinydd

The A/B box that was in use until 1994 had a 5p (old shilling) slot at the front and a 10p (florin/two shilling) at the rear. There was a stock of coins kept on the island - it was emptied by the local sub-postmaster/part-time BT engineer, Shetland pony farmer, part-time fireman etc He just recycled the coins in the box! It was on the UK's most remote inhabited island!

Thanks for that information. I'm sure that's the box I was thinking of. Was it on Fair Isle?

Just wondering, do you know when the last pay-on-answer payphones were taken out of service? I didn't come across any after the end of the '80s but I do remember that System X digital exchanges had a test number 175. When called, it did a ringback test on your line, then offered a selection of further tests. I seem to recall that dialling option 3 generated the pay tone for a few seconds, followed by the message "Incorrect coin pulsing". I assume that this test was for the coin-operated pulse generator mechanism in pay-on-answer coinboxes, and thus System X must have supported such phones, though as I said, I never actually saw any in use by the time System X arrived.

[hamid_1]

Originally Posted by Hermitcrab

The payphones with the red LED display were the trial version <edit>

In 1982 BT decided the trial was successful and ordered several thousand units, these being the second version with some improvements which included the change to a black LCD display. To most people though the 2 versions would have looked much the same.

I found a photo of the Mk.II LCD version, called CT22B - see attached.

I also agree with your earlier point that the old pay-on-answer phones often failed to work correctly, leading to frustration. I'm sure almost everyone who used one must have experienced difficulties at one time or another with coins jamming or not being accepted.

I actually have a mechanical GPO Payphone 735 in my small collection of payphones. It's fascinating to observe the fantastically complex coin mechanism although not surprisingly my example doesn't fully work either. There's no dialtone when the coin mech is plugged in. I cheated and used the engineer's shorting plug supplied with the phone to bypass the switch contacts. This enabled it to work as a normal phone without coins.

Take a look inside the mechanical payphone 735: http://www.telephonesuk.co.uk/images...one_inside.jpg

[Graham G3ZVT]

The early "blue" payphones switched to DTMF after the call was connected, for end-to-end signalling but was of limited use because of the absence of star and hash keys, the initial call was set up with pulse even on digital exchanges, I understand this was an anti-fraud measure, but does anyone know exactly what the exploit was?

When you dialed 144 to make a chargecard call, the earpiece would mute and you could faintly hear the phone sending a string of DTMF, then it would unmute in and you would hear the normal voice prompt asking for your user no & PIN.

Presumably the 'secret' string was the phones identity for when CLI was not available on an modernized exchange, but why was an ID needed?

Does anyone know how it was formatted and if any "D" column letters were involved?

[Robsradio]

Originally Posted by hamid_1

I found a photo of the Mk.II LCD version, called CT22B - see attached.

I also agree with your earlier point that the old pay-on-answer phones often failed to work correctly, leading to frustration. I'm sure almost everyone who used one must have experienced difficulties at one time or another with coins jamming or not being accepted.

I actually have a mechanical GPO Payphone 735 in my small collection of payphones. It's fascinating to observe the fantastically complex coin mechanism although not surprisingly my example doesn't fully work either. There's no dialtone when the coin mech is plugged in. I cheated and used the engineer's shorting plug supplied with the phone to bypass the switch contacts. This enabled it to work as a normal phone without coins.

Take a look inside the mechanical payphone 735: http://www.telephonesuk.co.uk/images...one_inside.jpg

This is something I have sought for many years, I had always hoped to stumble across one randomly, but it's never happened.
I guess it is the electro mechanical side that appeals most, probably not very likely to stumble across one these days as they have been out of commission for donkeys years now. Very nice though

[Pellseinydd]

Originally Posted by hamid_1

<snip>

Thanks for that information. I'm sure that's the box I was thinking of. Was it on Fair Isle?

Just wondering, do you know when the last pay-on-answer payphones were taken out of service? I didn't come across any after the end of the '80s but I do remember that System X digital exchanges had a test number 175. When called, it did a ringback test on your line, then offered a selection of further tests. I seem to recall that dialling option 3 generated the pay tone for a few seconds, followed by the message "Incorrect coin pulsing". I assume that this test was for the coin-operated pulse generator mechanism in pay-on-answer coinboxes, and thus System X must have supported such phones, though as I said, I never actually saw any in use by the time System X arrived.[/QUOTE]

It was on Foula, way out in the Atlantic to the west of the Shetland Islands. I found it in the exchange when I went there in July 1995 to recover the exchange - the last public electro-mechanical exchange in the BT network.

Re POA - they were certainly working into the early 1990's as I remember seeing them in some of the Halls of Residence.

I know TXE4 used the old 'Strowger' C&FCs for POA - I was senior commissioning engineer at Birmingham Rectory. The UXE7 had solid state plug in C&FC cards - the only ones I know of - there are some in the loft here!

[Pellseinydd]

Originally Posted by hamid_1

<snip>
I also agree with your earlier point that the old pay-on-answer phones often failed to work correctly, leading to frustration. I'm sure almost everyone who used one must have experienced difficulties at one time or another with coins jamming or not being accepted.

I actually have a mechanical GPO Payphone 735 in my small collection of payphones. It's fascinating to observe the fantastically complex coin mechanism although not surprisingly my example doesn't fully work either. There's no dialtone when the coin mech is plugged in. I cheated and used the engineer's shorting plug supplied with the phone to bypass the switch contacts. This enabled it to work as a normal phone without coins.

Take a look inside the mechanical payphone 735: http://www.telephonesuk.co.uk/images...one_inside.jpg

You must have a faulty mechanism. My Tele 735 work as a ordinary phone without a C&FC in circuit. Luckily I have some C&FCs which were still in the UAX12s I recovered for preservation in the early 1990's. I've also got one of the PCBs made several years ago to replicate a C&FC. You dial the number and when it sees 'line reversal' (no longer on BT lines - you've got to ask for it to be setup) it gives the paytone pips. It then counts coin pulses from the POA and lets you speak for so long before it sends more pips and you put more coins in for more time. Doesn't differentiate between local/trunk calls but at least you can see how the 'system' worked.

[julie_m]

I remember the "Blue Payphones" from the mid-1980s, although they were already requiring a minimum of 10p to make a call. What we now know as a "Payphone 500" or 600 was originally designated "Blue Payphone 2". The keypad buttons were initially made of blue plastic, but these were soon replaced with metal in response to vandalism (people were setting fire to the buttons with cigarette lighters and, according to some accounts, inhaling the fumes to get high). This was just one of numerous upgrades made to BT payphones over the years.

Payphone lines were LD-only because otherwise, it would be possible to lift the handset, inject DTMF tones onto the line (the mic was muted, but you could still couple a signal in via the speaker and/or hearing-aid coil) and get a free call that way.

Note that while it was possible in the USA to accumulate payphone credit at the exchange by playing tones down the line to indicate coins being inserted, the system in the UK worked the opposite way around; the phone kept its own track of credit, and counted down in response to pulses sent down the line from the exchange.