2 Sep
2017
2 Sep
'17
noon
On 2017-09-02 09:32 AM, Rob Janssen wrote:
We used the PI2 card here at UBC, using the original pi driver and then
the dmascc driver once it was available. It was a bit of a fiddle to
find a clear IRQ/DMA on crowded machines but dedicated router boxes (an
old XT worked) were pretty stable. Losing ISA slots on newer computers
meant that we were limited to older systems.
With two local mountain top repeaters on UHF (using custom duplexors) we
had a handful of users over 70-80 km paths ... kept my dad online for
several years before cables modems made it to the farm :)
Eventually the remaining users lost interest and I gave up after the
last repeater went down. At $800-1000 for a working system it just
didn't get enough people to sustain itself, and cheaper broadband meant
many of the original users didn't find it worthwhile.
Still have two repeaters worth of gear cluttering up my storage, hard to
let go of a project that took so much of my time !
... Niall
A couple of
decades ago, the "GRAPES" WA4DSY 56kbit modem kit was
available for a moderate price. They weren't too difficult to put
together. Alignment did take a scope, but took only a few minutes. About
five people in San Diego had them. As far as I know, only three ever
made it onto the air here.
I remember that modem, but also I remember that there were quite some
issues at that time.
It was not easy to reliably make 56k HDLC using affordable hardware at
that time.
For interrupt-per-character serial devices the performance of a PC-XT
was not quite enough.
There were DMA-based controllers but they were difficult to obtain, hard
to find reliable
drivers for, and expensive.