From mboxrd@z Thu Jan 1 00:00:00 1970 From: athornton at gmail.com (Adam Thornton) Date: Fri, 28 Feb 2020 07:34:50 -0700 Subject: [COFF] 52-pin D-Sub? In-Reply-To: References: <905CE999-5601-4521-847B-B2146C60B564@serissa.com> Message-ID: A RocketPort multi-serial sounds really, really likely for an astrophysics data collection instrument. Thank you! Mystery probably solved! The 8250 was unbuffered or maybe had a 1 byte buffer, the 16450 had a 1-byte buffer, the 16550 had a 16-byte buffer. I remember vividly how much better my life got when I got 16550 serial ports for my '386. Adam On Fri, Feb 28, 2020 at 7:12 AM Clem Cole wrote: > Adam/Dave, > > For whatever's it's worth, in PC/AT ISA bus times, at least one of the > serial port vendors (RocketPort was the vendor IIRC), used a DB-52P > connector, that connected to an interesting 'tail' which had 8 DB25P > connected to the DB25-S at the other end. This allowed 6 data conductors > (RCV/XMT/RTS/CTS/CD/DTR) * 8 ports, plus 6 grounds which again IIRC they > interspersed among the remaining 6 ground pins. > > What I remember is that it was this specific board that was one of only a > handful serial boards[1] that could run UNIX properly and hang Trailblazer > modems off of it because they not only fully pinned, but they had > single-chip custom USART with a good bit of buffering and hardware-based > RTS/CTS flow control. I think I may still have one somewhere, as I saw the > cable for it when I was looking for something else over the Christmas > holidays. > > [1] The original PC/AT used the NS8250 UART with no input buffering, which > went through a couple of generations, eventually begat the *550 version and > had I think an 8 character input buffer. But IIRC none of them had > hardware flow control. I forget the # now, Moto made a nice dual UART > with 16 chars of input buffering, that many of us on Unix workstation > business used, but when we moved to BSD 386 and Linux, we were stuck with > PC hardware, which had a particularly hard time with things like the > Trailblazer (which was the modem of choice for UUCP). > > Clem > _______________________________________________ > COFF mailing list > COFF at minnie.tuhs.org > https://minnie.tuhs.org/cgi-bin/mailman/listinfo/coff > -------------- next part -------------- An HTML attachment was scrubbed... URL: