Unknown TTY ICs

I asked the question over on the Greenkeys list where all the Teletype experts hang out. I got this reply, Date: Sun, 1 Feb 2015 14:05:00 -0600 From: Paul Kasley <kasley at fnal.gov> To: chrise at pobox.com, greenkeys at mailman.qth.net Subject: Re: [GreenKeys] Fwd: Unknown TTY ICs Teletype did indeed make their own ICs and they did indeed mark them ?TTY?. My first assignment as a co-op in 1973 at the T7 R&D facility was to profile PN junction depths on diffused wafers. The R&D fab was on the first floor of T7. Just off the T5 cafeteria was the epitaxial deposition lab. The PMOS manufacturing facility was on the north side of T3. TTY custom ICs went into the model 43, the model 40, and certainly other products that came after my time there. The initial process was P-channel and they did eventually make N-channel devices. Tag Waggener was a WECO guy that came to TTY in ?73 to lead the effort. He chronicled it in ?Teletype, We made That Data Move? (self-published on lulu.com). -Paul Kasley W9TS Tag's book, http://www.lulu.com/shop/herbert-a-waggener/teletype-we-made-that-data-move… Chris N0JCF On Sunday (02/01/2015 at 07:00AM +0000), tony duell wrote: -- Chris Elmquist