Comparing British 706 and American 500 and AE 80 'phones.

[BDM]

Stephen, that 300 design is very similar to the earlier AE design used in AE40 sets, as an example. Stromberg-Carlson 1243 sets stay engaged as you rotate them. They make a very audible click as you spin it to the chosen number. When I say AE design, I mean in base design only. Most manufactures changed certain aspects of the dial mechanism to their own design.

Here's an example of an AE. I'm at work now and cannot post pics of the SC or Kellogg variety. They're different, but very similar.

[Stephen Furley]

Yes BDM, that dial looks like the one in my AE 80.  I can't take any decent pictures at the moment; I'm out of processing chemicals for E6 film, and so is the shop that I buy them from.  I borrowed a digital camera from work to take the pictures in this thread, but there are no instructions with it, and I don't know how to use the thing.  It flashes at random when it feels like it, even though I seem to have the flash turned off, and it has auto focus which seems to focus on anythng except what you want it to.  I've never used auto anything on a camera before.  Most of my cameras don't even take batteries, e.g. the 5x4 inch MPP monorail that I've been using this evening.  I've now got another seve sheets of film to process hen I get the chemicals.

The first picture in this section is of a 706 from the back.  The small cicuit board is the regulator which automatically adjusts the volume of the sound to compensate for different amounts of line loss.  It can be unplugged and turned round so that the three connected pads at the top of the picture are in the socket.  This takes it out of crcuit, which is required for certain configurations, e.g. in local battery mode.  I think this brings us to one of the most important things about the 706, the fact that it can be easily converted to many different configurations.  There was no need to stock many different versions of the 'phone for things like shared service, local battery, PABX recall, extension plans etc. all that was needed was to take a standard telephone, add an extra part of two, move a few straps on the terminals and you had the necessary special model.  This idea was carried even further on the 746.

Let's take an example.  The GPO 'N Diagrams' were published for many devices; in the case of telephones the diagram number is generally 100 greater than the model number of the telephone, so let's have a look at diagram N806:

http://www.samhallas.co.uk/repository/n_diagrams/0000/N806.pdf

Thanks to Sam Hallas for making many of these available.

This document provides a drawing of the 'phone, the basic circuit diagram, various notes, and instructions for converting it for various special purposes.

It was also possible to make changes which were not anticipated when the model was designed.  For example, when the new-style tepephone sockets were introduced in 1981 the bell capacitor was moved from each telephone to just one in the master socket for each line.  Bells were to be wired in parallel for extension 'phones, rather than in series as before, and the impedance of the ringer was changed to 4000 Ohms rather than 1000.  The short thick lines on the circuit diagram are the links between the terminals.  As issued there were six links:

T8-T9, T4-T5-T6-T7, T16-T17 and T18-T19.  The 'A' wire of the line is connected to T17 and T18, and the 'B' wire to T8.  Converting to the new system is simple:

Remove old line cord.

Either replace the old ringer with a new one or connect a 3.3k resistor in series with it (by removing the strap between T4 and T5 and connecting the resistor in its place).

Remove the strap T6-T7.

Fit a strap between T17 and T18.

Fit a new line cord, 'A' wire to T18, 'B' wire to T8, and the bell wire to T6.  Job done.

Switches fitted in place of other straps could provide things like Earth recall, bell on/off, microphone mute, etc.

Somebody kindly provided me with links to the circuit diagrams for the WE 500 and the AE 80:

http://www.telephonecollectors.org/library/weco/500cd.pdf

http://www.telephonecollectors.org/library/aeco/ae80a.pdf

It's quite interesting to compare them with that for the 706.

Somebody commented on the way the hook switch can be flipped down on the AE 80 when the cover is removed.  I discovered only yesterday that the 706 and 746 can both do something similar; both have a small latch which can hold the switch down.

Before we leave the 706, one last picture of two later ones.  On the right is a concord blue one with a coloured plastic dial.  This came to be seriously broken.  I was restoring it, but the restoration is now on hold.  It's badly yellowed, it should be close to the colour of he dial ring.  I've been using resin coloured to match the colour as it is now, but I want to try the hydrogen peroxide treatment on it, and if it works, then the colour won't match, so I need to do that first.  On the left is an ivory one with the latest type of clear plastic dial fitted.  Note that this is now an all-figure dial, with the numbers on rhw dial plate itself, and a blank dial ring.  This one has also been fitted with a switch and button for bell on/off, and there is a handle fitted at the back; this was not fitted to the earlier ones.

Tomorrow, a very quick look at the 746.

[BDM]

Very interesting Stephen I'm getting an education in the British telephone models. Over all, operating principle is the same. Very little differences. Allow me to show you what I consider our closest American model to the 706. Stromberg-Carlson's 1243 - 1543. The 1243 was a metal body and looked very similar to the 1543, which was produced with a soft plastic body, and subdued curves from the 1243. The 1543 was produced well into the 60s to compete with the W.E. 500 & A.E. 802 (or "80").

The 1243 started production right after the big war. Like I said, it looks like the W.E. 302 on the outside. But inside, it used the first true completely contained potted network. This network was used until the end of 1543 production sometime around 1964/65 (not exactly sure when it ended) The 1543 network could be setup almost in any fashion as you've described the 706. Local-batt, common-batt, grounded(divided) or bridged(metallic) ringing, etc. etc. If you wanted to make a wall phone out of it, simply replace the switch hooks with curved ones, and a new shell. Bingo! You had a wall phone. BTW it's interesting what you stated about the later ringers.

Notice the dial workings. Not a great pic and I apologize, but SC changed to a completely modified dial mechanism with the 1543. The governor looks like it will interchange with any A.E. type dial. But that's where it ends. The switch hook contacts are completely enclosed. So are the dial contacts. I've also noticed the A.E. 80 switch hook contacts are enclosed. The last pic is of an early potted network A.E. 80 for comparison to your later set.

First three pics are an SC 1543 dial, then pics of the set itself. The last two are the A.E. early model 80.

[Stephen Furley]

That 1543 looks interesting: I'll have to try to acquire one someday.  There are two on Ebay at the moment, but I can't spend any more money at the moment.  If there are two now I'm sure another will come up sometime.  Did Kellogg produce anything similar?

I'm typing this on the road by the way, returning from Cheltenham to london; I'm near Windsor at the moment.  Both 240V power and Internet access is provided on the coach.

[Dennis Markham]

It's a miracle.........the internet and the technology we have at hand that is now common place.

[Stephen Furley]

I'm home now; I wanted to write just a few lines about the 746 telephone which replaced the 706, but I haven't had tome to do it yet.

When I arrived home two boxes were waiting for me, containing two telephones recently bought on Ebay, which are the last two models in the series, and they're very interesting..

The 700 was the prototype, and had the new components and new-style handset, in an old 300-style Bakelite case; I've never seen one.

The 706 was the production version, with the thermoplastic case,  There were a couple of special variations, the 710 could take four buttons, and the 711 was a wall-mounting one.  The first wall mount version, the 1/706 was actually just a standard 706 With the dial turned 180 degrees, a metal rest to guide the handset so that the side of it pressed the switch.

In the updated series the 746 was the standard 'phone, the 740 had four buttons, and the 741 was the wall mount.

Then there are the two which arrived today, the 764 and the 782.  They use a standard 746 base, case and chassis, but a special circuit board and quite a few extra components, to convert them into - push-button models.  The 764 is 10-button LD, and the 782 is 12-button DTMF.  To take them in reverse order, and deal with the 782 first,  it's almost a standard 746, there are three extra terminals, only one of which seems to be used, a plastic plate covers the normal dial hole in the case, with holes in it for the buttons, and a module consisting of a keypad and a small circuit board replaces the standard dial, and mounts in the same way.  Mine is dated 1983, after privatisation, and it seems a bit odd that they should have have introduced a new odle this late based on such an old design; maybe they just had a lot of 746 parts to use up.

The 764 is quite different, and probably one of the most pointless 'phones that I have ever seen.  It has a similar plate to cover the dial hole, but with only ten holes in it, and larger ones to fit the larger buttons.  The circuit board is drilled and labeled to take the three extra terminals, but only one is actually fitted, and that is not used.  The push-button module is huge, bigger than a conventional dial, with several circuit boards, lots of components, and a sealed box on the back which contains, who knows what?  There's an extra terminal strip to provide six more terminals, an extra set of hook switch contacts, some sort of component containing mercury, I'm not quite sure what that is, a few other odds and ends, and a Ni-Cd battery, which is dead, so it won't dial.  I'm hoping I can open the battery and put new cells in it.  The battery is charged from the line, so I can't see why the 'phone can't be powered directly by the line, as the later one is.  All of this complication, it looks like it would have been very expensive to produce at the time, to provide the same functionality as a normal dial.  The buttons are really stiff, it's quite hard work to press them.  I'm not surprised that few of these things were made.

One other odd thing; the Telephone Lines shop in Cheltenham has a similar pair of 'phones, but the LD one has small buttons, while the DTMF one has large ones, the reverse of my pair; I don't know why.

[Stephen Furley]

In 1967 a new model was introduced to replace the 706; the 746.  The differences were quite minor, the shape of the body around the handset was changed somewhat to give it a more modern look; it was also said to be easier to keep clean.  The case was now secured by one screw at the back, rather than two on top, and the carrying handle was stronger, and an integral part of the moulding, rather than a separate part.  An extra colour, dark brown, was added to the range.

Inside there were also changes, mainly to reduce costs.  The circuit board was greatly reduced in size, to little more than half the size of the one in the 706, and now contained the components of the regulator, which was no longer a separate part.  The reduced size of the pcb meant that the ringer was now mounted on the base of the telephone, rather than on the board.  The capacitor was changed from a large metal can type containing both to two much smaller plastic ones.  In some early models one of these was actually two smaller ones wired in parallel.  The traditional springset for the hookswitch contacts was replaced by a small microswitch mounted on the base.

While the 706 could only have one switch and button fitted, the 746 was capable of being fitted with two, with half-width buttons.  All buttons were now in clear plastic, as were dials, reducing the number of different parts which had to be stocked.The frame in which they were fitted was actually capable of taking four, but this needed a different body, the model 740.  A number of other parts could be fitted, including up to three sets of extra hookswitch contacts.  Dials were now all-figure, no letters, as the later 706s had been, the numbers were now printed on the dial plate itself, with the surrounding ring being blank.  Blank rings had also been fitted to some later 706s.  These were moulded in solid plastic of the appropriate colour, unlike the old ones which were coloured at the back, with the numbers and letters printed, and then covered with clear plastic.  Again, this would have reduced costs, and also, old two-layer rings tend to deteriorate over time.  Also, the rings for the 746 were made with lugs at the back, and were simply rotated slightly to lock them into place, removing the need for the metal clip ring used on the 706.  Early models still had a metal base; later ones had plastic.

That's about it. A couple of pictures comparing the 706 wit the 746, and one of the inside of the 746.  I've fitted two switches to this one, a push button for bell on/off, ans an extra pair of hookswitch contacts which can be seen in the last picture, but which doesn't actually do anything; I've just wired it up to some spare terminals to show how extra parts could be fitted.  I can't show the two push button versions at the moment because I've got them soaking in the peroxide mix to try to remove some of the yellowing.

To be honest, I really think there's very little to choose between any of these four 'phones from the point of view of the average user.  All have their advantages and disadvantages, but they're only minor

[McHeath]

Interesting stuff, cost cutting was clearly going on everyplace in the 60's as the American phones were getting cheaper parts as well to save money. 

All this cost cutting eventually leads to all our phones being made overseas, mostly in Asia it seems. 

Still waiting for my 706 to arrive from Israel.

[bingster]

For $5, it's probably coming by a combination of fishing trawler, carrier pigeon and overland stage.

[McHeath]

LOL

[Stephen Furley]

Very interesting Stephen I'm getting an education in the British telephone models. Over all, operating principle is the same. Very little differences. Allow me to show you what I consider our closest American model to the 706. Stromberg-Carlson's 1243 - 1543. The 1243 was a metal body and looked very similar to the 1543, which was produced with a soft plastic body, and subdued curves from the 1243. The 1543 was produced well into the 60s to compete with the W.E. 500 & A.E. 802 (or "80").

The 1243 started production right after the big war. Like I said, it looks like the W.E. 302 on the outside. But inside, it used the first true completely contained potted network. This network was used until the end of 1543 production sometime around 1964/65 (not exactly sure when it ended) The 1543 network could be setup almost in any fashion as you've described the 706. Local-batt, common-batt, grounded(divided) or bridged(metallic) ringing, etc. etc. If you wanted to make a wall phone out of it, simply replace the switch hooks with curved ones, and a new shell. Bingo! You had a wall phone. BTW it's interesting what you stated about the later ringers.

Notice the dial workings. Not a great pic and I apologize, but SC changed to a completely modified dial mechanism with the 1543. The governor looks like it will interchange with any A.E. type dial. But that's where it ends. The switch hook contacts are completely enclosed. So are the dial contacts. I've also noticed the A.E. 80 switch hook contacts are enclosed. The last pic is of an early potted network A.E. 80 for comparison to your later set.

First three pics are an SC 1543 dial, then pics of the set itself. The last two are the A.E. early model 80.

grounded(divided) sounds like it would be the way that we used to do shared service, with one subscriber's bell being connected between tip and earth, and the other's between ring and earth; is that what it is?  I couldn't even begin to guess what bridged(metallic) ringing is.

There are still two 1543s on Ebay; if the cheaper of the two is still there after next payday then I might be tempted.  The 'phone is cheap, but the postage would be getting on for twice the cost of the 'phone itself, and then I would have to pay 15% (of the total cost including postage) VAT, plus handling fee of eight pounds, which would make it expensive.  The cost of posting a 'phone from the US is something like $50, and some lamps which I sent in the opposite direction cost almost as much, but a few weeks ago I bought some equipment from China, which would have beed similar size and weight to a 'phone, and that only cost about ten pounds to send.

I've just discovered this:

http://www.ericofon.com/catalog/classic2/ne540.htm

and this:

http://www.ericofon.com/catalog/classic2/leich105d.htm

I like the look of that NE 540, but I doubt that I'll ever see one.

The Leich convertible is a very similar idea to the 1/706 over here.

[McHeath]

I've got an Ericofon from the Ericofon.com fellow and it's very nice.  He does, or at least on this phone did, great work. 

[Stephen Furley]

Very interesting Stephen I'm getting an education in the British telephone models. Over all, operating principle is the same. Very little differences. Allow me to show you what I consider our closest American model to the 706. Stromberg-Carlson's 1243 - 1543. The 1243 was a metal body and looked very similar to the 1543, which was produced with a soft plastic body, and subdued curves from the 1243. The 1543 was produced well into the 60s to compete with the W.E. 500 & A.E. 802 (or "80").

I shouldn't have done, but I've bought a black 1543.

I'm still interested in the North Electric 540 and Leich 105 on the Ericophone site; I've never seen either of them; maybe one day.

[BDM]

Great! I'll be interested in hearing what you think

[bingster]

grounded(divided) sounds like it would be the way that we used to do shared service, with one subscriber's bell being connected between tip and earth, and the other's between ring and earth; is that what it is?  I couldn't even begin to guess what bridged(metallic) ringing is.

Everything you ever wanted to know about party line ringing methods (shared service) in the US and Canada, courtesy of the Bell System Memorial:

Party Lines in the U.S.A.
- a blast from the past!

July 6, 1999

Courtesy of CLAUDE STERLING


WHY PARTY LINES

In the early days of the telephone in the US, telephone circuits consisted of one wire with a ground return. Circuits were few and there was little interference from electric power distribution. As demand for telephone service increased in urban areas, it was necessary to migrate to "full metallic" i.e. two wire lines. Multi-pair telephone cable had not been developed, hence each line required crossarm space for two pins and insulators. In high density urban areas there was a limit to the number of crossarms that could be places on a given pole.

In rural areas, great distances between farms became a barrier to economic pole line "open wire" construction. Many rural or "farmer" lines were constructed by the farmers themselves. Sometimes the lines consisted of a single wire attached by a porcelain knob to a two by four nailed to a fence post.

Given the above economic and physical barriers, party lines became a feasible solution to providing service to all who needed it.




CODED RINGING

In the early days of party line service, the ringers on all telephones were "bridged" across the telephone line or in the case of one wire service connected line to ground. Whenever there was ringing current presented either by the operator or by a subscriber turning the magneto on his telephone, all telephones on the line would ring. In order to differentiate what party the call was for, a system of coded rings was developed, usually a combination of long and short rings.

Example: Telephone number 46F31, in this case, the "F" indicates "Farmer Line", the 46 is Farmer Line 46 and the 31 is the ring code - three long rings and one short ring.

Other schemes were used where the last digit of the phone number denoted the ring code, last digit 1 denoted one long ring, 2 denoted 2 rings - - - up to five and then 6 would be one long and one short, 7 one long and two shorts etc.

Rural lines frequently had as many as 20 parties and the telephone was ringing all of the time. A means of reducing the number of rings heard by a party was desirable. In those days the concept of everyone having a one party line was unthinkable!


RINGING SCHEMES

Several methods were developed both by the Bell System and the Independent Companies to reduce the number of rings heard by a given subscriber. At this point we probably need to take a look at some definitions. Going back to basics, the telephone circuit in its simplest form consists of two wires, i.e. "tip" and "ring". This terminology originates from the plug on the operators cord which has a tip contact and a ring contact.

TIP - Usually the green lead in the line cord.
RING - Usually the red lead in the line cord.
GROUND - The yellow lead in the line cord which is/or was connected to the ground point at the protector where the telephone line comes in to the building. In the central office, this lead may be referred to as the "sleeve lead" again from the sleeve of the operators cord plug.
BRIDGED RINGING - All ringers on the line are "bridged" or connected across the tip and ring leads of the line, hence they all ring at the same time and every party hears all rings.

Since there was usually some form of lightning protection at the premises, usually carbon blocks with an air gap to the ground rod, a ground connection was readily available at the customer premise. Since ringing current is not readily affected by stray noise sometimes present on a ground return, the ground (or earthing electrode for you good folks in the UK) can be utilized as a return path to the central office.

SELECTIVE RINGING - By utilizing the ground return, several methods are available for reducing the number of rings heard by any given subscriber.

FULL-SELECTIVE RINGING - Regardless of the number of parties on a given line, an individual subscriber hears only his own ring.

SEMI-SELECTIVE RINGING - Each party hears only half of the rings on a given line.

DIVIDED RINGING - Half of the ringers on the line are connected tip to ground and half ring to ground. In this manner, any given party only hears half of the rings on the line. In the case of a two party line, each party hears only his own ring (Full selective ringing). In the case of four or eight (or more) parties, a subscriber hears half of the rings on the line (semi-selective ringing).

Up to this point, things are pretty simple, a single telephone set can be used for any application. From here on, the stocking of sets becomes a bit more complicated.

SUPERIMPOSED RINGING - Here, 20 Cycle ringing current is superimposed over a DC bias, either negative or positive. With this arrangement, four party service can be Full Selective and eight party service Semi-Selective. This arrangement requires either a relay or gas tube in each telephone to detect the DC bias and respond appropriately. It is necessary to use a special set with the gas tube and each set must be configured on site for the particular party code. Superimposed ringing was widely used in the Bell System.

(+) Bias, Tip to ground
(-) Bias, Tip to ground
(+) Bias, Ring to ground
(-) Bias, Ring to ground

FREQUENCY RINGING - (See Ralph Myers book page 48) Uses five different ringing frequencies hence five types of ringers. This makes stocking of sets a little more complicated. With Bridged Ringing, 5 parties can be Full Selective, with bridged ringing, 10 parties can be Full Selective and with Superimposed Ringing, 20 party Full Selective Service can be achieved. Stromberg Carlson in the XY switch did indeed accommodate 20 party full selective service. Frequency ringing was rarely used by the Bell System but it was widely used by the Independents phone companies.

HARMONIC RINGING - the most common form of Frequency Ringing where the ringers were tuned to 16 /23, 33 1/3, 50, and 66 2/3 cycles per second. Since these are true harmonic frequencies, false ringing became a problem in some cases. AE solved this by using "non-harmonic" frequencies of 16, 30, 42, 54 and 66 cycles per second. I think Gary Goff mentioned having an AE40 with a 54 cycle ringer in Southern California. Another variant was "Decimonic Ringing" utilizing 20, 30, 40 50 and 60 cycle ringers. With the advent of more sophisticated electronics, these frequencies could easily be derived from the commercial 60 cycle commercial power.

This may be like asking for the time and getting a response of how the clock works but in essence this is why most WE sets have straight line ringers and many Automatic Electric, Stromberg-Carlson, North and Kellogg sets have "tuned" ringers.