From: Michael Davidson <michael_davidson_at_pacbell.net>
Date: Sun Jan 12 18:06:13 2003

Ethan Dicks wrote:

>--- Michael Davidson <michael_davidson_at_pacbell.net> wrote:
>>If memory serves, a DLV11J 4 port async serial interface would be
>>a good place to look since they are not particularly hard to find
>>and I *think* (sorry, I don't have one I can look at right now)
>>they have 4 DC003 chips on them.
>Probably not 4 x DC003. Probably 4 x DC005. Probably 1 x DC003.
Since it's a 4 port serial card with each channel having both a TX
and RX interrupt associted with it, and the DC003 is the chip that
handles the interrupt request / acknowledge protocol for 2 interrupts
you actually *would* expect that there would be 4 x DC003 *and* 4 x DC005.

I just found my one "real" DEC DLV11J and it does, in fact have
4 x DC003, but only 3 x DC005.

My guess is that since the DLV11J occupies an unusually large range
of addresses they didn't need the address decoding capabilities
that a full set of 4 x DC005 would have provided and they substituted
a cheaper set of bus drivers / receivers for the 4th DC005.

Michael Davidson
Received on Sun Jan 12 2003 - 18:06:13 GMT

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