[TUHS] What's with the DZ-11?

Noel Chiappa jnc at mercury.lcs.mit.edu
Fri Nov 28 00:55:09 AEST 2014

    > From: Clem Cole <clemc at ccc.com>

    > 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.


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