Newsgroups: comp.robotics
Path: brunix!sgiblab!news.cs.indiana.edu!cyliax@cs.indiana.edu
From: "Ingo Cyliax" <cyliax@cs.indiana.edu>
Subject: Re: Wireless RS232 link
Message-ID: <1994Mar13.112954.8721@news.cs.indiana.edu>
Organization: Computer Science, Indiana University
References: <24.4764.2500.0NB2DC1D@pcohio.com> <KONOLIGE.94Mar11235501@ocean.ai.sri.com>
Date: Sun, 13 Mar 1994 11:29:51 -0500
Lines: 42

In article <KONOLIGE.94Mar11235501@ocean.ai.sri.com>,
Kurt Konolige <konolige@ai.sri.com> wrote:
>In article <24.4764.2500.0NB2DC1D@pcohio.com> andrew.jenkins@pcohio.com (Andrew Jenkins) writes:
>
>[stuff deleted]
>> Uhhh, excuse me, but have you ever looked into purchasing a professionally 
>> constructed radio modem? First off, most require an FCC licence to operate, 
>> and second, they are outrageously priced! I have been investigating just 
>> such a purchase for the facility I work at, and prices in the neighborhood 
>> of $2000 per unit are what I've seen. (granted 9600 baud, but...)
>> 
>> $200 is not unreasonable if the error rate for this *thing* is low.
>> 
>> Regards,
>> 
>> Andrew "Just putting my 2 cents in where it's not wanted" Jenkins
>> 
>> ---
>>  * WaveRdr 1.0 [NR] * UNREGISTERED EVALUATION COP
>
>CommRad has a spread-spectrum 900Mhz radio modem for $429/pair.
>Full duplex, up to 38400 baud, although I've only gotten reliable
>transmission at 9600.  --kk

Actually, I'm not sure they are spread spectrum, they operate on the
900Mhz cordless phone band, I think. BTW, is 900Mhz cordless phone
band spreadsprectrum or not ? I have gotten them to work at 38,400Kbaud,
between Sun Sparcs. I.e. unless you have a system that can handle
38,400Kbaud, you will have to get hardware handshaking to work, which
I haven't figured out yet. With a regular PC, I have only gotten
9600baud. Range is OK. Dropouts are common especially when moving, 
with an apropriate datalink protocol (v42 or MNP4) they would seem
more reliable.

They are pretty impressive units, we are evaluting them for a project
that envolves wiring a bunch of PCs together in a stadium. They can
be setup for one-to-one or one-to-many and since they are serial,
writing drivers for them is pretty easy. 

-ingo
-- 
/* Ingo Cyliax, cyliax@cs.indiana.edu, +1 812 333 4854, +1 812 855 6984 (day) */
