There are four options I see.

1)  use a standard 16550 and crank it up to 115Kbps.  With the VJ =
compression, you can probably get a few extra Ks out of it.
2)  Boca and a few other companies sell a board with enhanced 16550s =
(16560) that has a larger FIFO and doubles the clock frequency with a =
register setting.  It's kind of weird working with them, but in the end =
you can realize 230Kbps.
3)  If you are set on 2Mbits, try laying your hands on an old Arcnet =
card, however there is no support for Arcnet under NetBSD.
4)  So go for the gold, use a 10 Mbit card, what's an extra 8Mbits (just =
a little more bandwidth ;-)  I remember reading in a amateur radio =
magazine, several years ago, I read of a couple of guys who wired two =
network cards up to their microwave dishes.  I seem to remember that =
they were at a distance of 10 miles (line of sight).  I can't tell you =
what equipment they were using, I lost the article and can't remember =
which magazine it was (I subscribed to 10 back then).  If you bought a =
cheep NE2000 or get a good Etherexpress 16 with a 10base-T (twisted =
pair) connector, you're set!  10base-T is nothing but a super high speed =
serial device, you have a + and - TX and  + and - RX, no flow control =
data to worry about!

To be honest, #4 is what I've always wanted to do, but I just don't have =
the time or anyone line of site to play with...

jam


----------
From:  Alex Barclay[SMTP:alex@vsys.com]
Sent:  Friday, May 23, 1997 6:00 AM
To:  netbsd-help@netbsd.org
Subject:  FAST Sync Serial cards

Hi all,

This isn't exactly a NetBSD question but that is the only OS that I
currently run at home and you guys seem to know about computer IF
cards.

I'm looking for a card that can perform _fast_ (well for normal
serial anyway) HDLC. I'm looking at a target rate of about 2MBit.

Now... Just because you don't know of one quite this fast could you
please let me know what you do know about. I would be interested in
any card shifting more than 256Kbps.

Second... Don't worry about there not being a driver for NetBSD. If I
like the card then there soon will be one ;-)

You're probably interested in what this is for..... No.. Well I'll
tell you anyway:

I live about 3 miles from my office on line of sight. So I'm
constructing a radio link in one of the Ham microwave bands that will
give me a high speed link. Having done the link budget I think that I
can easily get 2MBit without breaking the bank on RF devices, or
completely filling the Ham band that I choose (1300MHz is currently a
good choice)

If you can't think of a good card then do any of you know of any good
serial controllers that can do this. I looked at a 8530 and it seems
to max out at about 2MBit with a 16MHz clock. What I mean here is that
the hdlc cct can run that fast but it leaves precious little time for
the bus interface to get the data into the host CPU.

Finally I'm interested in ISA or PCI - but preferably PCI as I'd like
to perform some kind of DMA transfer and I've never liked the ISA way
of doing this.

All ideas greatly received,

Alex.

--=20
Alex Barclay			E-mail: alex@vsys.com
731 N.Weber, Suite 202		Tel:    +1 719 635 8066 x 17
Colorado Springs		Fax:    +1 719 635 1420
CO 80903