[TenTec] Why Ethernet?

[Grant Youngman]

I don't think anyone would argue that Ethernet is the right 
technology for networking computers and servers.  

> I did some looking and I don't find RS232 to Ethernet adapters.

There are quite of few of these products (E'net to RS232) on the 
market, e.g., from Lucent ORiNOCO and Neteon as two examples.  
A lot of industrial equipment is RS-232 controlled, and the guys 
who've invested in that equipment aren't going to replace it for lack 
of an Ethernet interface ...  The price range for E'net to RS-232 
seems to run in the $150-200 range list.  So if you have to have an 
E'net connection today, you can certainly do it.  Generally, you end 
up essentially Telnet'ing to the converter -- which is just plain old 
serial, and I'm not sure you'd even save a cable anywhere, at least 
not in the station.

Of course, it isn't just Ethernet that's the issue.  Do you want to 
Telnet to the radio? Do you want the radio to speak XML?  Do you 
want the radio to serve up HTML so you can access a "soft panel" 
from a thin client (e.g. your browser)?  And what about security if 
you decide to offer yourself this access over an Internet connection, 
especially if you're going to want to push the PTT from the remote 
location? Lots of questions, that go well beyond basic issues of 
Ethernet and TCP/IP.

The idea of accessing and operating the radio over the internet 
pretty much requires that you be able to serve up receive audio and 
send transmit audio using voice packetization technology, and that 
raises a lot issues, mostly related to delay, jitter and quality of 
service, and their impact on audio quality.  Sadly,  it just won't work 
reliably over today's Internet, period,  because (1) you can't control 
what the other guy is the doing, and (2) the Internet (as opposed to 
what you can do in your own home or corporate network) isn't 
QoS/DiffServ enabled, which is absolutely essential for packetized 
audio.

(This isn't true for "streaming" audio, but streamed audio for a 
number of technical reasons (mostly jitter buffer size) won't work 
well for typical two-way VOX-like conversations.  It's fine if you just 
want to listen to your rig from grandma's house.

For in-station control, the USB idea is a pretty good one  -- and the 
conversion from/to legacy RS-232 is relatively inexpensive and 
simple.  You could do it today.

Grant/NQ5T



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Grant Youngman /NQ5T
http://www.globeking.com
nq5t at attbi.com