roy@phri.UUCP (Roy Smith) (02/15/88)
More and more, I'm falling in love with Farallon's PhoneNet system;
anybody who has ever run more than a trivial amount of wiring will surely
appreciate the joys of hooking up a new network node by simply punching
down a pair of wires in the phone closet. This has led me to wonder about
totally replacing RS-232 with AppleTalk. My idea is to have a small cheap
box which has an RS-232 interface on one side, an RJ-11 jack on the other,
the required electronics to convert RS-232 to PhoneNet, and the smarts to
run telnet.
Any number of these boxes could talk to various hosts through a
single Kinetics box, making an easily and cheaply expandable terminal mux.
I don't know what the total aggregate throughput of a kbox is, but I
imagine it could easily handle dozens of 9600 baud connections. I also
don't know what it would take in the way of processing power to run telnet,
but I can't imagine it's much more than a 68000 with 64k ROM and maybe 4k
RAM. NCSA Telnet on the Mac is only a couple hundred k, most of which is
probably devoted to screen handling and the VT-102/Tek-4014 emulation, not
to mention multiple connections, command-key processing, ftp, and a host of
other (much appreciated, but non-essential) bells and whistles.
If you wanted to dedicate a kbox to just this function, you could
put the telnet smarts in the kbox and make the distributed AT/RS-232
adaptors even cheaper, having them talk a simple private protocol with the
kbox. A kbox costs about $2k. I figure you could build and sell the
distributed parts for not much more than $100. Even for a relativly small
number of ports, this works out to way below the $3-500 per port most
terminal muxes seem to cost, not to mention being a lot more flexible and
easy to install; anywhere you have a single unused pair of phone wire (i.e.
just about everywhere) you can hook up a terminal in 20 minutes.
BTW, this is number two in a continuing series of hair-brained
schemes to do strange and wonderful things with kboxes and PhoneNet wiring.
Last time I wanted to build a 230 kbps etherbridge out of a pair of kboxes
with a LADC circuit in between. The general opinion of the many people who
responded was that while it was a neat idea it wouldn't work because kboxes
can't pass enough packets per second to be useful, they don't have full IP
routing capability with the currently available software, and the LADC line
probably doesn't have enough bandwidth. Oh well, it *did* sound too good
to be true.
--
Roy Smith, {allegra,cmcl2,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016