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

[BDM]

Stephen, as you know that's a 60/hz ringer. With the proper capacitor across the ringer, you may be able to get it to ring. I generally can on our 20/hz system.

[Stephen Furley]

I might try that; how do you calculate the value for the capacitor?  We never had anything like this here, all ringers were 25 Hz.  We had shared service a long time ago, but it was two parties, with ringers wired tip to earth and ring to earth.

[Stephen Furley]

We've looked at the 706 and the 746, but right at the end of the 'standard' telephone era a few push-button variants of the 746 were produced.  There seem to have been several minor changes in a short period, but I've got a couple here, the LD 764 and the DTMF 782R (R for Recall).  As can be seen in the first picture, the 764 has larger buttons, but I have seen a LD 'phone with small buttons, and a DTMF one with large buttons.

The 764 contains a lot of extra 'junk', including a battery, which is missing in the pictures because I'm trying to find replacement cells which will fit it.  Most functions of the telephone work without it, but it cannot dial.  The keypad module is larger than a dial, and there are also extra hook-switch contacts, a relay, and various other components.  This thing is also heavy, about the same weight as a 500.  Inside the casing, you can see that it is a standard 746 one, and the buttons only just fit through the dial hole, the top corner ones extending into two notches.  The four smaller notches are normally used to secure the outer dial ring on the 746, and the two slightly larger ones are for the finger stop, one in the normal position, and one inverted to turn it into a wall 'phone (with a special handset rest).  I really cannot see any point in the 764, it does nothing more than a 746 with a conventional dial will do, needs a lot of extra components, including the battery, which would have increased maintenance, and I'm pretty sure it would have been more expensive to manufacture at the time.

The 782R is much more like a conventional 746, except for the DTMF module replacing the dial, and a couple of extra terminals on the main circuit board through which it injects the tones into the line.  This is also much lighter than the 764.  This would have been intended for PABX use; hardly any public exchanges supported DTMF then.

These two telephones should be the same colour by the way; the 'yellow peril' strikes again!  Note that the 764 has a metal base, whereas the782R has a plastic one, as did later 746 sets, and as did the Mk.1 706 about twenty years previously.

While not exactly rare, neither of these models was very widely used; they carried a higher rental charge than a standard telephone, and the design was becoming rather dated by this time.  Smaller, lighter and cheaper telephones soon became available.

[gpo706]

Them AE80's look nice, I would have to stumble over this 5 days before payday!