From mboxrd@z Thu Jan 1 00:00:00 1970 From: jnc@mercury.lcs.mit.edu (Noel Chiappa) Date: Thu, 27 Nov 2014 09:55:09 -0500 (EST) Subject: [TUHS] What's with the DZ-11? Message-ID: <20141127145509.5C8F418C0C7@mercury.lcs.mit.edu> > From: Clem Cole > two issues. first DEC subsetted the modem control lines so running > modems - particularly when you wanted hardware flow control like the > trailblazers - did not work. ?? We ran dialup modems on our DZ11s (1200 bps Vadics, IIRC) with no problems, so you must be speaking only some sort of high-speed application where you needed the hardware flow control, or something, when you say "running modems ... did not work". Although, well, since the board didn't produce an interrupt when a modem status line (e.g. 'carrier detect') changed state, we did have to do a kludge where we polled the device to catch such modem control line changes. Maybe that's what you were thinking of? > To Dave the DZ was great because it was two boards to do what he > thought was the same thing as a DH To prevent giving an incorrect impression to those who 'were not there', each single DZ hex board supported 8 lines (fully independent of any other cards); the full DH replacement did need two boards, though. Noel