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Date:      Tue, 23 Jan 2001 10:46:15 +1030
From:      Greg Lehey <grog@lemis.com>
To:        "Michael C . Wu" <keichii@iteration.net>, Brad Knowles <brad.knowles@skynet.be>, Kris Kennaway <kris@FreeBSD.ORG>, freebsd-chat@FreeBSD.ORG
Subject:   Re: GSM vs. CDMA (was: VCD (was Re: cvs commit: src/sys/dev/ata atapi-cd.c))
Message-ID:  <20010123104615.B16006@wantadilla.lemis.com>
In-Reply-To: <20010121182033.C44819@peorth.iteration.net>; from keichii@iteration.net on Sun, Jan 21, 2001 at 06:20:33PM -0600
References:  <200101211447.f0LElEk04073@mobile.wemm.org> <KAECKEJJOLGHAFGGNIKMAELICAAA.res02jw5@gte.net> <20010121145018.A73989@citusc17.usc.edu> <20010121165422.A44505@peorth.iteration.net> <v04220821b691222656eb@[10.0.1.2]> <20010122103136.L93049@wantadilla.lemis.com> <20010121182033.C44819@peorth.iteration.net>

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On Sunday, 21 January 2001 at 18:20:33 -0600, Michael C . Wu wrote:
> On Mon, Jan 22, 2001 at 10:31:36AM +1030, Greg Lehey scribbled:
>> On Monday, 22 January 2001 at  0:46:38 +0100, Brad Knowles wrote:
>>> At 4:54 PM -0600 2001/1/21, Michael C . Wu wrote:
>>> However, Europe made the "leap" to TDMA technology in GSM, before
>>> CDMA existed -- standard AMPS/NAMPS style analog cell phone
>>> technology had been stretched beyond its limits, and they had no
>>> choice but to go digital.
>>
>> It's true that GSM is a TDMA technology, but it's definitely not what
>> is called TDMA in the USA.
>
> GSM is a set of protocol for mobile phones, and so is PCS.

As I've mentioned before, PCS is a term meaning "digital wireless
telephony", and thus covers GSM.

> I tend to think of them as being comparable to TCP vs. UDP.
> Believe it or not, the OSI 7-layer useless model applies
> to mobile phones and telecomm too.  We have counterparts
> to TCP/IP OSI model in the mobile comm OSI model.
>
> Why do I think that OSI model is useless?  To paraphrase/quote
> wpaul: "Nobody in the real world uses the OSI model, it was created
> just so that professors and other people can make paper tests that
> have no importance other than making students memorize useless
> things."

I think this is a one-sided viewpoint.  Yes, the OSI model is deeply
flawed: when they designed it, they didn't have a good understanding
of what layers would really make sense.  But the concept, rather than
the implementation, is still very useful.

>>> 	The same will happen in the US, as 3G takes over from existing
>>> TDMA, CDMA, AMPS/NAMPS networks, but at least many of those
>>> companies will have relatively less money thrown down the TDMA hole
>>> which they then have to completely write off.
>>
>> Don't forget that they have recently started introducing GSM into the
>> USA.  I've found that it works better than the CDMA service.  This has
>> nothing to do with the relative merits of the technology, but with the
>> fact that the service providers learnt that their cell placement was
>> too sparse for the old analogue/*DMA network, and they placed them
>> closer for GSM.
>
> Yes, I recently switched from AT&T PCS to Voicestream GSM in America.

What kind of PCS were you using before?  And how's the GSM coverage in
Austin?

Greg
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