News:

"The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them." - Dan/Panther

Main Menu

Amtsanschließer 33 German wwii telephone / trunk

Started by dsk, April 25, 2019, 11:41:09 AM

Previous topic - Next topic

dsk

The Amtsanschließer 33 or Amtsanschliesser 33 is a combined CB telephone and a trunk for connecting the LB field telephones or fieldexchange to:
1) a cb system
or
2) an LB system with automatic ring-off.  (This system closes a dc path when the caller goes on hook, but runs the off hook signals trough a capacitor, totally opposite of what a CB system does.

The right one her is the Amtsanschließer 33
The German WWii alterantive is the Amtzusats 333: https://bre.is/CjpcYQq3j

dsk

I got a question about using the capacitors C1 and C2 as the isolation between CB and LB circuit.
I would have used a transformer if I should design the circuit, and that is also done in newer circuits. 
On the other hand, the US SB-22 board also use a capacitor for this purpose.

In a modern circuit containing semiconductors the transformer will protect better.

dsk

19and41

Your link was to a thread about your German Dial phone with the field phone handset.  Could you put up the info on your new dialer? ;)
"Any sufficiently advanced technology is indistinguishable from magic."
— Arthur C. Clarke

countryman

Here are some more pics.
This individual set is stamped "DR" (Deutsche Reichsbahn, german railway) - 1940. (DR later became DB in West Germany, in the east the "Reichsbahn" name persisted) The railway used LB phones and also an automatic exchange separate from the public phone system, called BASA. My guess is that this set was used for years after WW II by the west german "DB" railway as a trunk between both systems. I have it from a junk dealer from Hagen, which is a major railway junction. The (younger) receiver element is stamped with a DB logo. There is a sticker "Fw München-Aubing" inside, where it may have been refurbished.
The whole unit was covered with the thickest layer of cigarette tar I ever saw. Did I destroy the patina by cleaning it ;-) ?
The "Klinke" plugs are very similar to regular phone jacks, but a little longer.

19and41

Nice looking phone.  I think when that material is clean, it allows one to see how it was made with fabric being part of the material.  I would think that would have more interest than the remains of the tobacco smoke.  The phones of this type I see here, I have not seen anywhere else before.  Thanks for sharing the pictures.
"Any sufficiently advanced technology is indistinguishable from magic."
— Arthur C. Clarke

dsk

Looks like it just was upgrade to get it cleaned.  ;)
The only jack you may need will be the Vermittlungsklinke, and yes a 1/4" plug fits...almost.  You ma get one of those with molded plastic, and trim off a little, and it fits. (or you may adjust the jack in the phone)  Then it will actually fit as a trunk for the American field exchange SB-22/PT to.  ;D 


Not sure about what handset DB used, but this is different from what the German forces used. (maybe older)


dsk


PS, the capacitors may be bad, smart to test if you think about using it.  DS

countryman

Thanks for the tip! The caps test OK so far (with low voltage) but I do not plan to use it as a trunk to field phones. As you stated above, even good capacitors are a poor protection, more so when the phone is hooked to a computer system like I do.
Indeed the handset does not look original. It should have a push-to-talk switch. It looks like a W28 handset (older Siemens model).
It is often said that he "shabby" look comes from inferior materials. But in fact the phone survived almost 80 years, some obviously under rough conditions, without cracks and the bakelite still has a certain flexibility.  My guess is, the military just did not want a glossy black look. 
The pic is from the cleaning operations. I used plastics cleaner in a pump spray can, like suggested for outdoor furniture etc., that worked good.

dsk

The handset is probably older than the phone, and will probably fit the German W28  (designed 1928)

Now I have got some x-German field telephones (FF-33) stored in the garage. They probably went out of service as alte as in the 1970ies, and are not expensive here. That will be the right handset. for your phone.

I have worked more on the US SB-22/PT  in the last, and there the trunk has only that capacitor in one of the wires. 
It really works.  I use it connected to an old exchange so I do not risk my ATA by using it.
dsk

dsk

I see that some has find the German diagrams hard to read, so I hope this will help.
And of course with 4 terminals, and you shall not use more than 2 ...

Green numbers are just to identify terminals location.

dsk

dsk

The induction coil is equal to the one in the German w28
The balancing coil/resistor in paralell with the transmittercapsule "steal" pretty much of the DC current.
A resistor in series with the wire from terminal 5 will help.  220 ohms works, and may be hidden in a black shrink tube.
A better, but less diskrete solution would be a 330 ohms resistor shunted by a 2uF capacitor.