Because there will be other devices which will require higher bit rates &
bandwidth and therefore a communication physical layer and communication
protocol capable of supporting the other nodes in a distributed
architecture. If these other devices are real-time or moreover require Hard
Real Time communications, then 232 just will not come anywhere close to
providing this capabilty.
Since we will need such higher bit-rate & higher bandwidth services, we
might as well adopt a protocol which will be able to support thr
requirements for all the nodes in such an architecture. The slower devices
will function just fine. Personally, I like ethernet and TTP-C, running on a
twisted pair (~ 5mb/sec/channel x 2= 10mb/sec. for non-safety critical
applications) or perhaps MOST again on a twisted pair, since our
requirements are not for safety-critical and therefore will not need a true
Fault-Tolerant protocol.
Ethernet is the way to go, if we want to use a "solid physical" layer.
802.11b could be another approach, particularly if the address codes for the
various nodes use encrypted packets and where the encryption key is
effectively the address code...but this discussion will explode into an
endless subset of endless explainations, and I don't want to go here.
Mark
----- Original Message -----
From: "Jerry Harley" <wa2tti@worldlynx.net>
To: <tentec@contesting.com>
Sent: Monday, June 02, 2003 7:45 AM
Subject: Re: [TenTec] Why Ethernet?
> Why would you want to spend the money of encoding packets at 10mb to
> control a simple radio or rotor. It is like putting a 500hp pump and a
> fire hose into you glass of milk?? RS232 and USB among others are great
> for what they are doing, and cost .033 or less.
>
>
> At 09:12 PM 01/06/2003 -0400, you wrote:
>
> >Well, I agree about Ethernet for networked computers. My sales and order
> >fulfillment system at work has 21 workstations, and two servers. The
> >inventory
> >system has its own server and five workstations. And as CEO,CFO, and
tech
> >wonk I
> >have to keep all that up. Even when the pickers insist on deleting
inventory!
> > But.....
> >
> >Sooner rather than later someone is going to cut costs and put a <$5.00
USB
> >interface in place of the RS232 port on rotor controllers. And the next
> >generation of auto-tune amps. And the next generation of all the other
> >computer
> >controlled shack accessories. Because the USB port is cheaper to build in
> >than the
> >legacy serial port; because it will take less effort to convert programs
to
> >use USB or Firewire than Ethernet; and because nearly every computer
> >built in
> >the last three years has either or both USB and Firewire. While an
increasing
> >percentage have no "legacy" serial or printer ports at all.
> >
> >To further complicate life many if not most modems already have a singe
> >ethernet port built in. But most of us want to use the shack computer
for
> >internet
> >access. Meaning at least one more card - or a separate router. Meaning
one
> >more piece of equipment taking up space I have dedicated to something
else,
> >and a whole bunch more cables to try to keep sorted in the restricted
> >space in
> >back of the equipment. Or give it up and go to thin Ethernet - I don't
> >think!
> >
> >
> >A single daisy chained USB line could serve the rig, amp, antenna tuner,
> >keyer, and whatever else you might have hooked to your computer. And do
it
> >with
> >short branch cableing. So a USB port would currently be more useful to
"Joe
> >Average Hamm" than an RS232 port if the rig and accessory manufacturers
> >modernized their equipment. Something that's going to happen fairly
> >quickly the way
> >'232 driver chips are disappearing from the catalogs.
> >
> >Since USB/RS232 adapters are still fairly common and fairly cheap the
> >transition to the newer mode would be much easier, allowing a mix
> >of USB, or
> >Firewire, and "Legacy" RS232 equipment. Without obsoleting the equipment
> >we already
> >have, or requiring a major upgrade of most late model computers.
> >
> >On the rig side - RS232 seems to do an adequate job of doing what needs
to be
> >done. The alternatives might do it faster - but how much faster do you
need
> >to update the frequency on your rig? Or change bands remotely? '232
> >works at
> >57 kbytes or some such - and I saw a demonstration of Firewire carrying
> >streaming video.
> >
> >I did some looking and I don't find RS232 to Ethernet adapters. I suppose
> >someone makes an adapter of some sort, as there are plenty of stand
alone
> >print
> >servers. I failed to locate any - but I didn't have time to look through
all
> >33,000 odd hits, either. But they must be fairly rare if even a casual
scan
> >failed to turn up any.
> >
> >That means converting the shack from what I have to Ethernet would be an
> >expensive proposition. I would have to consider the situation very
carefully
> >before I placed an order for an Ethernet enabled rig - and not much
> >thought at all
> >to placing an order for a Firewire or USB ported rig.
> >
> >Of course, it appears the ideal solution would be to do both. Spend the
extra
> >three bucks or whatever and add both USB and Ethernet to the next
generation
> >high end rigs. You can have your cake and eat it too.
> >
> >73 Pete Allen aC5E
> >_______________________________________________
> >TenTec mailing list
> >TenTec@contesting.com
> >http://lists.contesting.com/mailman/listinfo/tentec
>
>
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