[GreenKeys] 5A stock ticker

[John Nagle]

W2HX wrote:
>> PS. I also have two 5A black boxes, one was a donor for the other. Jack
>> K0TTY got one of them working a few years ago. I have yet to find the time
>> to reproduce his set up! 

     Those things get no respect, because they're so blah-looking.

     They're not really "tickers"; they're Teletype printers that
take a special six-bit code.  The electrical input is polar; the
line reversed polarity rather than simply being on-off, but it's
ordinary 6-bit start-stop async.  See

    http://www.prc68.com/I/WU5A.shtml#5APC

who found that 80VDC through 750 ohms at 50 baud would work.

They were probably set up for polar operation because previous
ticker networks were set up for polar operation, and they could
thus change out the machines without rewiring the transmission
system.

					John Nagle