From mboxrd@z Thu Jan 1 00:00:00 1970 From: dave at horsfall.org (Dave Horsfall) Date: Sat, 29 Feb 2020 08:58:40 +1100 (EST) Subject: [COFF] 52-pin D-Sub? In-Reply-To: References: <905CE999-5601-4521-847B-B2146C60B564@serissa.com> <6a44c9e7-1e7b-bd0e-df1c-6e2208e8b780@kilonet.net> Message-ID: On Fri, 28 Feb 2020, Clem Cole wrote: > DZ-11 sucked... for a number of reasons, the SW issue being just part of > them, but they were short pinned and really did not do modems well, > particularly high-speed ones like the Trailblazer.  As you said, you > could make them work, but why bother? We used ours for local terminals only; 8 DZ-11s on the 11/70 worked fine (I don't recall how fast, but probably around 2400/4800). As I said, it came down to the driver. > Unix folks figure out the best idea was to use the Able DH/DM -  > cheaper, only one unibus slot for 16 ports (as opposed to 2 for the DZ), > fully wired on the DB25 end, hardware flow control and just worked > better in that is will DMA.  What was not to love... Sure, but then DEC Field Circus won't touch the box. > FWIW:  One of the guys behind DZ (who I will leave nameless) also > screwed up the first serial port on the Masscomp MC/500 after he left > DEC. I got there too late to fix it in the first version of the CPU > board.  So it was not fixed until I tore him a new one and educated him > on how RS-232 actually worked (I was the first lead for the data com > group as well as 1/2 the OS team).  I never quite understood why HW > folks often though of the serial port as '3-wires' -- sigh. Heh heh :-) I don't think I've ever seen RS-232 used "properly" i.e. implementing DSR/DTR or RTS/CTS for other than flow control etc, and using the secondary pins as well. -- Dave