[GreenKeys] Information Pleeze

[H.E.Robert]

Larry,

You are correct.  From the Bell System stand point,  all circuits must 
have a means to test, and isolate trouble, i.e. opens, shorts, and 
grounds, and loop length.  The private line configurations usually 
contained more than one Teletype on the loop, and unlike radio, each had 
to be physically connected to the loop, in serial fashion.

Using the stunt box and motor control relays, the machines could be 
addressed on an individual or group basis.
But being a loop, any "open" in the loop, disables the entire loop, so 
it's important that everybody is "in the loop".  The Bell System used 
resistance, capacitance, inductance and line balance to trouble shoot 
and isolate circuit troubles.  And as you say, the old Morse land line 
keys, had a shunt switch to close the telegraph loop, when you were not 
sending from your "key"!

I know everybody probably knows all this, just consider it a memory test 
for me! ;-)

Just Bob!

Larry Tighe wrote:

> Thanks to all for the shunt relay and test functions.  I guess the 
> shunt on the line proves continuity to the test bureau....too, I think 
> "old" teletype (Morse code) loops were all in series and going off 
> line would break the loop if not for a shunt.
>
> The reason I'm probing all this is, I want to operate the 28's in as 
> original condition as possible.  I don't want to "jigger" it but keep 
> it factory original.
>
> Again, many thanks to all...lots more questions to come :>)
>
> lar
> _______________________________________________
> GreenKeys mailing list
> GreenKeys at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/greenkeys
>