[GreenKeys] Telegraph Signal Analyzer

[Duncan Brown]

Bob,

One of the original, generic, terms for a teletypewriter was a "printing 
telegraph", probably because they replaced telegraph equipment on the 
same lines.  Teletype Corp. used the term "Printing Telegraph" up into 
the 1950s.

The military used the suffix "TG" for both telegraph and teletypewriter 
equipment nomenclature.

This analyzer on ebay was designed for teletypewiter circuits on DC 
lines.  Long DC lines  had a lot of capacitance which would distort the 
TTY pulses.The RANGE control on a TTY is to allow the machine to find 
the best spot on the TTY pulses to read with minimum distortion.  Any 
extra distortion on the line or in the TTY transmitter contacts could 
make the signal unreadable.

So TTY equipment & DC lines needed to be continually checked for 
distortion.  When you have a short (feet, not miles) connection from 
your TTY to a modem or computer, distortion is usually not a problem.

Have fun,

Duncan
K2OEQ



On 01-Jun-22 11:00, Robert Nickels wrote:
> There are two of these on eBay, the other one is more expensive but 
> comes with a manual:  https://www.ebay.com/itm/175142507316
>
> "Telegraph" seems misleading, given the panel markings - I'm just 
> curious how these instruments were used - by a telco I'd guess?
>
> 73, Bob W9RAN
>
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