With good physical layer analysis one can EASILY compensate for latency
(temporal delays). On a production supply and station installation basis\,
it means a set of standarized physical layer lengths and some software
interfaces to accomodate for the associated delay function.
It is all a matter of analysis, planning & implementation. NOT more.
Mark,
KB8GKZ
----- Original Message -----
From: "Duane Grotophorst" <n9dg@yahoo.com>
To: <tentec@contesting.com>
Sent: Saturday, May 31, 2003 4:00 PM
Subject: Re: [TenTec] Why Ethernet?
>
> While USB and Firewire would certainly be capable of
> the bandwidths required for both streaming digitized
> signal data and control, they do have one big
> limitation, - distance. With Ethernet (running TCP/IP)
> there would be essentially no limit to the distance
> that your control/audio I/O panel could be from the
> radio itself (assuming the link has sufficient
> bandwidth and adheres to the Quality of Services
> protocols). The USB and Firewire technologies on the
> other hand are limited to just 10's of feet. Single
> runs of 100base-T Ethernet are good for 100's of feet;
> fiber can be into the 1000's of feet.
>
> Ethernet also is media independent; in other words you
> can use Cat 5, fiber optic, or wireless (QRM potential
> for operating on 902 MHz and 2.3 GHz bands though).
> Fiber optic being extremely useful for avoiding RFI
> issues. Fiber optic can also be very useful for
> managing lightning risks with tower (or tower base)
> remote mounted gear. You can get a reasonably priced
> and adequate RJ45 crimping tool locally. Then with
> some bulk Cat5 cable and a package of RJ45 connectors
> you can make your own TIA-568 spec network cables most
> any length you want (within the spec). And do this for
> much less money than buying Firewire or USB cables (or
> even pre-made Cat 5 cables). I don't think there are
> lot of "do it yourself" tools out there for making
> Firewire or USB cables.
>
> Ethernet is a totally open and well-established
> standard that has shown remarkable evolution while
> maintaining backward compatibility. This is important
> for our radios because they don't fade away in few
> short years like most consumer electronics do.
>
> The underlying logic for making the black box radio
> components talk Ethernet is for total versatility, for
> a standalone box radio a simple cross over cable is
> all you need. For more sophisticated station
> configurations it's just a matter of assembling a
> standard TCP/IP network using the inexpensive off the
> shelf and easy to acquire components that best match
> what you are trying to do.
>
> As for all those pesky existing RS232 devices they
> will be with us for a long time, unfortunately finding
> new computers with RS232 ports is increasingly
> difficult. And the USB to RS232 adapters are not
> always cooperative either. So for the foreseeable
> future I plan to use multiport PCI cards, you can get
> one with 4 RS232 ports for about $100, the one I have
> just works, no muss no fuss.
>
> Duane
> N9DG
>
>
> --- AC5E@aol.com wrote:
> >
> > I certainly agree it's about time to change to
> > something besides an RS232
> > port Including a serial port means the customer
> > must shop carefully to make sure
> > they can hook up their rig. Todays most common
> > choices are Ethernet, USB, and
> > Firewire. And then there's the other hundred "new
> > and improved" stars of
> > tomorrow. If they catch on - which most probably
> > will not.
> >
> > While there's nothing really wrong with the typical
> > Ethernet port, I don't
> > network my rigs all that often. But between the
> > rotor interfaces, computer
> > logging, keyer, amp interface, etc., etc., there are
> > a whole bunch of wires going
> > to the back of the shack computer and ham gear. Far
> > too many for either
> > comfort or easy servicing.
> >
> > So I would prefer either a regular USB or Firewire
> > port on a rig. At the rig
> > end, there's very little difference in cost of
> > implementation between any of
> > the common choices, and far more confusors come
> > with USB/Firewire than network
> > ports these days. A single strategically located
> > hub with a couple of more
> > daisy chained to it would sure relieve a lot of the
> > clutter around here.
> >
> > 73 Pete Allen AC5E
>
>
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