I have seen this board listed on eBay during the summer (several months).
From the 1970s to mid-1980s there were a variety of Morse/Bardot products (discrete & IC designs),
before the usage of Digital Signal Processors (DSP) in late 1980s (Texas Instruments & Motorola chips).
Since the FCC did not permit the usage of ASCII during the 1970s, the majority of the products
decoded Continuous Wave (CW)/Morse Code and 5-bit Baudot / Radio Teletype (RTTY). This changed by 1984 (AT&T Break-up).
The more advanced amateur radio products used keyboard (computer’s or dedicated)
to encode for transmission (Audio Output & Push-To-Talk)
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Curtis Electro Devices was founded by Jack Curtis, K6KU (sk, 2018 ).
Jack designed “purpose built” ICs at Signetics (his 8044 series) in 1970s.
This specific board was very expensive, and not often seen.
http://www.arrl.org/news/curtis-keyer-chip-developer-jack-curtis-k6ku-sk
The RCA Jack should connect to Audio Output of a Shortwave Receiver,
THEN tune the radio to a CW (Morse) or Bardot (RTTY) transmission.
greg
w9gb
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In mid-1960s Bill Henry (Illinois BSEE) founded HAL Communications in Urbana, IL (before A. Clarke/S. Kubrick “2001”)
and had a number of dedicated RTTY and CW products throughout same period (1970-1990s).
Bill retired in 2012 ... but is still with us.
http://www.halcomm.com/about/history/