On Wed, 18 Sep 2019, Jon Elson via cctalk wrote:
Oh, my Gosh! the first 3 pics are of a KTU phone
system. If you are OLD
enough, remember the phones with 5 line select buttons and a red hold button
below the rotary dial? That is what that unit supports, the 565 phone.
Please don't let anybody call the 25 pair 50-pin miniature ribbon
connector (RJ21), "Centronics"!