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SubjectRe: serial ports
   Date: Wed, 7 Aug 1996 16:29:45 -0400 (EDT)
From: "Andrew E. Mileski" <>

> The problem with why COM1 and COM3 can't share FIFO is electrical, not a
> matter of software. The problem is that the UARTS for COM1 and COM3 are
> directly driven by the board, and so if both UARTS are active, they end
> up fighting for the line

I wish people would be more careful when making all encompassing
statements like the above. Especially when in that context they
are plain wrong.

Every 2, 4, and 8 multi-uart card I've ever used or seen has the
extra logic required for electrically correct ISA interrupt sharing.

I wish people would *READ* the whole message before sending flames out.
If you had read the rest of the message, you will see that I addressed
multiport serial cards like the AST Fourport and the Bocaboard BB-1004,
BB-1008, and BB-2016. However, I stand by my original statement ---

The reason why you can're share COM1 and COM3 is electrical.
==== ====

This statement says nothing about multi-uart cards (which typically use
different I/O ports and IRQ's than the COM1/2/3/4, to reduce the chances
of port and interrupt conflicts). Multi-uart cards was addressed later
in the *same* *email* *message*. My entire message was was all
encompassing, if you had actually bothered to read it.


- Ted

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