[GreenKeys] Telegraph Signal Analyzer

[Sheldon Daitch]

 Bob, 
the answer to your question regarding AP and UPI depended on when.

The radio station in my small hometown in Georgia was an AP subscriber, and the telco loop was a DC circuit from the central office in town.  That was 1960.   
At some point in the mid to late 1960s, maybe even later, the AP wire was converted froma DC circuit from the telco to a tone pack feed circuit.   The AP used a Lenkurt 25 tone system, up to 25 AFSK circuits on one voice grade channel.  The Lenkurt unit at the APbureau was a rack mounted unit with the individual tone cards.  The Lenkurt unit atthe subscriber was a small box, about the size of a shoe box, with one tone demodulatorcard and a power supply for the loop current.

I believe UPI ran the same system.

Hopefully long past the statute of limitations - in the mid 1970s, I was working for someradio stations in North Carolina.  Election season and management wanted to do live reporting from the county elections office and they also wanted the UPI wire at that location.

I had contacted UPI for the cost of a short term circuit to the county elections office andthe price was, well, not within the budget.   I realized that the UPI circuit was a voice gradecircuit from "somewhere" and I just had to local telco establish a copper loop from the radio station to the elections office.   I jumpered the UPI tone pack audio over to the loop, picked up the UPI Extel printer and a roll of paper, took it over to the elections office and it worked fine.
73SheldonWA4MZZ



    On Wednesday, June 1, 2022, 12:31:57 PM EDT, Robert Nickels <ranickels at gmail.com> wrote:  
 When I worked at radio stations in high school and college, we'd routinelyorder up dedicated lines from the telco for special broadcasts, but that 
was audio, and you'd pay for the duration the circuit was up.   The AP 
or UP and weather teletypes ran from permanent lines (provided by the 
telco too I think) -  but those had to be copper, right?  Or did they 
send audio and convert it to current loops at the machine?     There 
would obviously be a limit on how far they could run a current loop 
signal, so it would make sense to convert to audio tones, or they use 
some sort of regenerator?     I would guess that local telcos 
distributed the signals on behalf of the originator (i.e. UPI, AP, 
National Weather Service, etc) to the radio and tv stations, newspapers, 
etc who subscribed to those services.

I remember there being interface boxes on the wall but never knew what 
they actually did.     My only concern was to make sure the machines 
didn't run out of paper so you'd have something to "rip and read".

73, Bob W9RAN

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