On Tue, 21 Jan 1997, Jukka Marin wrote:

> Well, the Cyclades cards use a chip which only has 12 bytes of FIFO for
> each port and direction.  If something blocks your interrupts for too long
> a time, you'll get FIFO overruns.

Ouch! That's less than a 16550. Perhaps that explains why the
Cyclades card was cheaper than the 8-port (and even some of the 4
port) 16550-based boards I've seen.

> On the other hand, if you swap the DTR
> and RTS wires in your serial cable, the Cyclades hardware can automatically
> negate RTS before the FIFO overruns.

So the Cyclades has the ability to turn off DTR automatically when
a FIFO is about to overrun? How odd. Is this settable per-port? Or
do I end up with a modem that hangs up if it overruns if I don't
have an extra cable with DTR and RTS swapped, and have to use a
normal cable instead?

> Cyclades was working on some real good serial cards last year.  I don't know
> if they are selling that card already.. if so, I think we should try to get
> a driver for it.  (I'd be interested in working on one if I had the time.)

They do have a second series, the Cyclom-Z, but it's twice the
price, and I can't use it in my application because it comes in a
PCI-bus version only. Besides, in my application I need only one
high-speed port, so it would be cheaper to buy a Cyclom-Y and a
Hayes ESP card.

cjs

Curt Sampson    cjs@portal.ca		Info at http://www.portal.ca/
Internet Portal Services, Inc.	
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