[GreenKeys] 5-A Teletype stock ticker on eBay

[W2HX]

I have two of these! WA2HWJ even got it printing for me several years ago. 

73 Eugene W2HX


-----Original Message-----
From: GreenKeys [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of John Nagle
Sent: Monday, August 11, 2014 4:33 PM
To: greenkeys at mailman.qth.net
Subject: [GreenKeys] 5-A Teletype stock ticker on eBay

Here's an exotic Teletype product - the 5-A stock ticker.

http://www.ebay.com/itm/Western-Union-Black-Box-Ticker-5-A-Stock-Quotation-Machine-Teletype-/251614845500

$250, plus shipping.  Condition looks very good.  No sign of rust, damage, or even dirt.  Comes with the "Description and Adjustments"
manual. Some museum should pick this up.

This is the "high speed stock ticker" introduced in the 1930s.
It's a 6-level start-stop machine with no shifts.  Compatible with nothing but some central stock quote transmitter. Input is polar - rather than MARK and SPACE, the line polarity is reversed. This follows previous stock ticker practice, so they didn't have to change the distribution network when the machines were changed.  Someone did figure out how to drive one with a PIC and an H-bridge:

http://www.prc68.com/I/WU5A.shtml

The description there is kind of confusing. I get the impression that early 5-A models had some kind of backwards compatibility mechanism so they could interoperate with older step-by-step tickers.  Later models were just 6-level start-stop machines.

Unlike the Edison glass dome tickers, which are expensive collectables, the 5-A, which isn't very pretty, never caught on with collectors.

I have no connection with this.

				John Nagle
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