Connecting a "mobile" Sun - SUMMARY

From: David C. Kovar (
Date: Mon Oct 29 1990 - 16:18:26 CST

  I recently asked if anyone had any suggestions on how to connect
a mobile (ie, in a car/van/whatever) Sun workstation to a stationary
one in our home office.

  The replies fell into the following three categories:

  1) Use Phil Karn's KAQ9 software and packet radio. We'd have to
     use the commercial bands and not the ham bands, but it is
     a viable option. Some problems, off the top of my erratic memory,
     would include throughput, lack of available channels in some
     areas, and licensing problems.

  2) Use Telebit's new cellular Trailblazer. I need to get more details
     on this but it looks like you can get up to 9600 baud (either
     directly or through compression) which would be adaquate.

  3) People asking for summaries.

  If I learn any more I will summarize again. Many thanks to all that


Here are the replies:



I don't know what applicability it would have to Suns
but there is a packet-radio ip & the related ka9q package
(from Phil Karn?) for the ibm-pc; I suppose the applicability
of this would also depend on how far from home base you wandered.
I'll ask around 'round here & see if anyone knows more, I
know this has come up at LBL a few times.


I dont know if I would try SLIP for your application. The best I have
seen a cellular phone do is 9.6 but I would guess that you could
use a Traailblazer and maybe get 19.2 throughput. The cellular phone
costs would be up there so I would think you would do it from
a hotyel if possible.

I guess you could lease some time on a VSAT type system but again I would
bet it is expensive.

The 'blast' protocol might work though. THey seem to get more out
of a communications line than any protocol Ive seen. Its better
than Zmodem and far better thatn UUCP & KERMIT etc. They have versions
for all types of systems.

Final Thought, You might find it easier and cheaper to use
Federal Express or UPS to sends tapes back and forth. If you data
can wait 12-15 hrs, the cost might be cheaper and it would be
better than starting a 10 MB transfer at 9.6.

Hope this advice helps,

Bill Lewandowski
Ford Aerospace


Yes, I have a Sparc station in the trunk of my car. The power comes
from an inverter, which takes 12VDC to 120VAC. The main issues are
1) running very thick wire from the car's battery (most convenient
point of access to car's power) to the inverter.
2) shock mounting the sun workstation. This means building a platform
which has resonant frequency other than the normal modes of the car.
I had a mechanical engineer friend build mine - he is a real
automobile consultant and you could probably hire him.

As for staying in touch with home, you'll want either a cellular
phone and cellular modem (ordinary modems are no good, cellular
is too noisy) or maybe some kind of packet radio/ham type system
if you have the license.

What else would you like to know?

Return-Path: mstar!

Telebit makes a "Cellblazer", which is a full-size IBM PC internal
card implementation of a Trailblazer Plus. You'd get FTP throughput
of 1.3-1.5Kb/sec over PPP.

Of course, not too many Suns of interest have IBM PC slots inside.
But there's recently been an announcement from somebody with a name
like "Mercury" of a box that has a 386 and a SPARC chip, with an AT
bus inside. This may be what you're looking for. Peruse recent
issues of the Sun trade rags (SunTech Journal, SunExpert, and Sun
Observer) for press releases and advertisements.


Return-Path: tessi!joey@nosun.West.Sun.COM

telebit supposedly has a cellular compatible modem.


Not worth including in your summary, but you might look into packet radio.
It might give you greater bandwidth than SLIP. I Don't know the details,
except that someone on your team will need a Ham radio license (which is not
difficult to get).



If I were in your shoes, I'd see how good the new CellBlazer cellular
modems from Telebit were. I've seen some advertising blurbs on these,
and they look like a modified Trailblazer -- but what I know about cellular
technology would fit on a PostIt note, so I can't comment on just what
sort of differences there are. But it seems to me that if you could
run at 9600 baud or faster, then SLIP becomes a distinct possibility --
at which point you then have the higher-level services such as ftp/telnet
at your disposal.

Hmmm, I wonder if a (mobile) CellBlazer can talk to a (stationary)
Trailblazer? (It would certainly make sense to design 'em that way.)
Hmmm, if that's true, and you're going to have 120 V available, what's
to stop you from using an ordinary Trailblazer? (I guess what I'm
getting at is that I'm wondering if there are any differences in the
prrotocol/error-checking between a CellBlazer and a Trailblazer.)
And it *that's* true, I wonder if you could run a Trailblazer Plus
at 19.2 Kbaud, which would be nicer for SLIP.

I would imagine that the Telebit people could probably cover this
ground with quite a bit more certainty than I can. ;-) I'd be
interested in hearing what you find out, whether it's along this
track or another one.


Return-Path: pegasus!

I think I saw something about Telebit offering a cellular modem, that would
be 9600-baud or better.

Richard Foulk


I'm not an expert on the subject, but Phil Karn's KAQ9 TCP/IP was written
to work over amateur radio; clearly TCP over radio is a possibility.
Of course, using the amateur bands for transmitting data as part of a
commercial venture violates FCC regs, but there may be other bands that
are acceptable.

I remember talking with somebody at Lamont Darhoty (sp?) labs about
how they transmit data to and from their research vessels at sea.
Apparantly now they use stock Trailblazers talking uucp over regular
high-seas telephone (i.e. satelite) connections. I think they have
a slightly hacked uucp which makes the connection startup a bit faster
to save on connect charges.


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