[Milsurplus] Re: [armyradios] SB-22A/PT Battery Holder question

[Brooke Clarke]

Hi John:

I have a photo of the inside back of the SB-22, can you take a 350 KB 
jpeg?  From my reading of the manuals when two BA-22 boards are combined 
to form a 29 circuit board, two SB-22 units are combined (latched 
mechanically toghther, but not electrically) and the operator pack in 
one of them is replaced by the spare line cards from the @ Accessory 
Kits.  If this was done and the SB-22 with all line cards was seperated 
and sold seperatly, then I would expect it to still have the clips and 
battery holdersunless they were removed to repair another SB-22.

I don't have a schematic, but think that there are a couple of terminals 
on the back for external batteries.  I think 3 Volts is needed to power 
the operator's headset and 3 Volts are needed for the night alarm lamp 
on the operator's pack.

There are terminals on the back for an emergency operator that might be 
connected to a field phone that would act as the operator's phone, but 
you may need to use a conference call technique for three phones where 
the first of the line packs is used just to get access to the operators 
field phone and the sedcond is for the calling party and the thrid is 
for the called party.  This is just a guess, since I haven't yet found a 
headset for my SB-22.

The MX-2915 Accessory Kit for the SB-22A contains 2 each TA-222 the 
standard link pack, and one each TA-326 Trunk pack.
The SB-22 Accessory Kit, MX-230A, contains 3 each TA-222 standard 
packs.  I think this is the only difference between a 22 and 22A.

I think the TA-326 goes off hook when the plug is pulled out and can be 
used with Common Battery signaling circuits, either a higher level 
switchboard or the Plain Old Telephone System.

See:
http://www.pacificsites.com/~brooke/SB22.shtml

73,

Brooke Clarke, N6GCE

J. Forster wrote:

> I have an SB-22A/PT telephone switchboard made by Bruno-New York and 
> it has no
> battery holder or clips for one. Anyone know the story?
>
> Also, how do you ID which line pack is for the trunk and are there 
> schematics
> available on-line. I have TM 11-5805-262-12 and there is little in there.
>
> Thanks,
> -John