From: Demetre Valaris (izizyyob@nidera.nl)
Date: Sat Jan 19 2002 - 12:28:13 EET
On 18 Jan 2002, at 23:20, Riley Williams wrote:
> Hi Demetre.
>
> > I know that SCS has a firmware that allows you to make your PTC-II a
> > modem that provides IP over SLIP, but I am not interested in that
> > since both ends on HF must use the same firmware and hardware and
> > then again IP over HF is a bit too much to desire!
>
> I'm no expert on HF as I'm not licensed for it, but there is one claim
> in there that is just plain rubbish, and easy to prove as such...
>
> > ...both ends on HF must use the same firmware and hardware...
>
> ...is demonstratably false even by a complete moron, and no better
> example of this can be found than AX.25 itself, which works quite
> happily not only with different firmware but with different brands
> using different chips to control them. Ethernet in all of its many
> guises also proves the same fact.
>
> The actual requirements are quite simple:
>
> 1. The signalling used for the link employs a standard protocol.
> To take FSK packet as an example, the two ends must employ the
> same shift between the mark and space frequencies, must shift
> between them at the same frequency (the Baud rate), must use
> the same number of bits per character (the Data Length), and
> must use the same framing format (the Parity and Stop Bits).
> This corresponds to level 1 (the Physical layer) of the ISO
> diagram.
>
> 2. The packet protocol must be the same for both ends of the link.
> This corresponds to layers 2 through 7 of the ISO diagram as
> applicable to the system under discussion.
>
> Providing both of these conditions are met, the link is possible.
> As to whether it is feasible, that depends far more on the details
> of the various protocols used than on anything in the above.
>
> Incidentally, the "same hardware" requirement claimed in your quote is
> an issue with requirement (1) above, and the "same firmware" requirement is
> an issue with requirement (2) above, so those are NOT the same thing.
>
> Best wishes from Riley.
>
Hi Riley,
Too much talk for nothing. Can you demonstrate a modem other than SCS
that does IP over HF without having to depend on a computer for the SLIP
protocol?? I do not think you can because there is none, at least in
the radio amateur market. So if you need an HF IP point to point link, I am
afraid that having 2 X SCS PTC-II is the only solution.
But after all I said clearly in my e-mail that I wasn't interested in that anyway,
so what is all this fuss about I do not understand.
Thanks for the e-mail anyway!!!
73 de Demetre SV1UY
e-mail tugha.hngmwbasa@rele.tunk.net
http://www.athnet.ampr.org/~sv1uy
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