Re: Cisco AX.25 support (was: Gracilis card question)
- To: firstname.lastname@example.org (Alan Cox)
- Subject: Re: Cisco AX.25 support (was: Gracilis card question)
- From: "Matti E. Aarnio [OH1MQK]" <email@example.com>
- Date: Tue, 28 Feb 1995 22:08:29 +0200 (EET)
- 19: 15 pm
- Cc: firstname.lastname@example.org
- In-reply-to: <m0rjUdp-00013hC@iiit.swan.ac.uk> from "Alan Cox" at Feb 28, 95 04:
> > But how many 4Mbps interfaces exist for the 486, and how many of them
> > could it support? Would you be interested in the project if you could
> > have T1 or better over the radio? (There is local interest in such a
> > product.)
> Well the PI/2 can allegedly do 2Mb/sec, and I'd put a bet on it being
> cheaper to design and build a fast I/O driven 4Mb/second board based on
> a 68302 than to buy a Cisco. [Im not saying you dont get good things from
> a Cisco, just its the wrong approach]
Actually I don't believe you can push more than 2Mbps (aggregated)
thru 68302's serial units.
I had a design with MC145488 (DDLC), however those serial chips
(HDLC only) were discontinued. It was able to push 2Mbps per
High-speed (Mbps) serial chips exist from Rockwell (cisco uses
them, but with external DMA..), Zilog, Motorola, Intel, AMD...
Some of them come to my mind (I have datas):
- i82586, i82596 (Ethernet AND HDLC) Mono channel, costly
- MC68360, MC68EN360 Quad channel, costly
- Z16C32 (aka Z16C320, markings appear to vary) Mono channel, cheap
Those all have internal DMA controllers, so a board with internal
buffer, or (heaven forbid!) busmaster DMA are possible..
I do like the internal buffer style :-)
You may be able to rework an ethernet board with i82586 into
a mono-channel FDX HDLC interface with speeds up to 20Mbps.
> With an ISA bus 4Mb/sec boards are going to be a problem at about 2 or 3
> from gut feeling, with PCI it won't be an issue.
Right. Do you have any good references on building PCI boards ?
Must I call Intel ?
/Matti Aarnio <email@example.com> OH1MQK