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SB-22/PT with rotary dial.

Started by dsk, January 27, 2016, 12:28:48 PM

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dsk

On eBay it has popped up lately several of these.  Are that special modifications, or standard.  I can not remember a dial as the part of the unit when I served, nor described in the documentation. I have a vague idea of the keypad addon possibility, but not seen that in use.

dsk

rdelius

The SB 22A was used by many countries.I have one with the touch pad add on, US built.The one on ebay might be from Europe judging from the dial. Even S Korea and Iran built these.

dsk

Thank you!
I'm pretty sure the one we used when I served was American, and it did definitely not have a rotary dial, nor a keypad. 

dsk

rdelius

The ones on Ebay are from or rebuilt in Austria.Have seen PRC 77s on Ebay from Austria lately also

dsk

I f I should buy one, I would like to have a USA made unit, how should I know where it is made?
dsk

rdelius

The USA ones were made by Star Dynamics,Federal, Stromburg Carlson and other compaines.
Might be rebuilt by Tobyhanna depot or no MFG on them but would be marked US Signal corps and or US.You could use circuit packs or headsets from the foreign ones for spare parts.Make sure the battery holder tube is included.If missing, hard to find.the US boards are twice as much
on Ebay.A good Austrian for modules  and a US chassis might be a cheaper way to go.They are in english on all

dsk

I feel that I wish I had one, and I definitely do not need one!
It is extremely interesting to analyze the circuitry, and compare to other field exchanges I have used.
(we still had one ex-German "kleiner klappenschrank" in service. And later I have tested one as pictured under)
The SB 22 is mad with modules, so it is extremely serviceable in the field!  :)
It has an integrated operators telephone also suitable for remote control of some radio sets.  :)
It has an integrated trunk line pack (may also work on LB lines) :)
It is made for 12 lines, that does not match my decadal mindset  :( if it had had 2 trunk lines I would never noticed.  :-X
It is heavy, to heavy to easily be carried up the hills to a shaded position, often needed in out terrain.  >:(
Each set has a pack of spares. Nice when needed, heavy to carry.  :-\
It has a dtmf unit. All other exchanges from the same time had rotary dials.  :):(
The wire terminals are not of most easy to use.  >:(
It has a lot of possibilities for external power, and ringer generators  ;D

What about the others, more compact/ light weight. Not as easy to service.
The line units does work pretty similar, (manually reset of the signal on the wartime unit) the circuitry of the line"packs" are remarkable equal.  The trunk line of the SB22 and the external trunk units of the wartime exchange are splitting local and trunk lines by use of capacitors. The newer German exchange has a transformer.
The European systems had rotary dials. The wartime unit uses a field telephone as operators "pack" (any field telephone)
All of them has proven to be reliable!

Why do I not want the European SB22?  I do not like the modifications. They have a strange circuit with a rotary dial for just one trunk line with a connector in a wire, and a modification just fixed with rivets on the side for external connection of a 30 pair cable to en external connection field.  I could have solved this with much more elegance by using available NATO components. I just do not trust it!  We had lots of old stuff when I served, but it was in top shape, and trustable.

dsk

dsk

As i mentioned over, I'm looking for an affordable US made SB22, but how do the rotary dial versions work? A quite different wiring diagram? or just modified to cover one trunk line?

dsk 

19and41

I served in a communications section from 1974 to 77 and there were no such accessories used nor issued with SB-22's.  The unit you have pictured appears to be of European manufacture.  I wonder if it connects to the set through the cable that can be seen to the right rear of the set?.  During the time I was working in communications such tactical equipment was segregated from ready use with civilian telephone systems, because as much as it pains to say, there were those who would use such equipment to steal services, such as long distance call time. A person who worked at an installation where I served was convicted of around $10,000.00 of long distance charges.
"Any sufficiently advanced technology is indistinguishable from magic."
— Arthur C. Clarke

dsk

I guess you are right. Touch tone was pretty late here, so rotary dial was the most reliable for field equipment, and could be connected to any random phone line found for a quick and easy use. Of course you could misuse this, but I believe that was kept as a"commonly known secret".
The European versions of the SB-22 looks (by pictures) like a pretty simple modification adding in a 30 pin jack for line cable (equal to e.g. exchange pictured earlier in this thread) On the other side they did ad on a cable and connections for a dial unit. (Pretty nasty way to do it) But how did it work? 

I am curious about that, but if I shall get one, I want the US made version equal to what I used during service in the early 80ies.

Some people her claims us to be so USA alike so we could be the next (51'st) state.  :-)

I am pretty sure the most of you will strongly disagree when visiting Norway, but for sure we have adopted many of your "ideas"

dsk

19and41

I know the SB-22 and TA-312 were the most reliable pieces of equipment we operated.  I guess If they work well there is no reason to re-invent the wheel to get a good piece of equipment. 
"Any sufficiently advanced technology is indistinguishable from magic."
— Arthur C. Clarke