[GreenKeys] Loop current supplies

[Nick England]

Also see the TMC equivalent at
http://www.tmchistory.org/tmc_manuals/manuals_db/psp/tm_psp-1-2_2_1_59.pdf

Nick
(phone email acct)


On Nov 9, 2013, at 7:09 PM, Jim Haynes <jhhaynes at earthlink.net> wrote:

> If you need to make a loop current supply, you might want to look at
> the instruction book for the Northern Radio Type 238 current loop control.
> 
> http://www.virhistory.com/tmc/tmc_pages/NorthernRadio/ib_238-1-2_4_8_66.pdf
> 
> This provides a constant-current circuit so you don't have to adjust the
> loop current as you switch machines into and out of a loop.
> 
> Another article with a similar design is in the January 1972 issue of QST,
> "The Modern Teleprinter Local Loop" by Frank Merritt VE7AFJ.
> 
> jhhaynes at earthlink dot net
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