On Fri, 22 Oct 2004 03:40:23 -0400, Pete Theisen <petet@acun.com> wrote:
> Hi Everybody!
>
> Anyone know of a good wireless broadband to use in Florida? I mean go
> from place to place even mobile like a cell phone with a PCMCIA card or
> something stuck into the notebook. Is there anything?
>
> Of course, this *has* to work with Linux as well as Window$.
>
> Regards,
I do "can you hear me now?" and find that the toss is between Verizon and
AT&T. Verizon uses CDMA and is running X1RTT which will give you on the
order of about 120kb on a good day.
AT&T uses GPRS and is introducing EDGE on all of it's sites. GPRS will give
you about 40-60 kb and EDGE will boost that to about 160 to 200 something.
They all leapfrog on another, Verizon had the 'edge' for a while, but now with
AT&T rolling out EDGE they will have greater speed.
Now here is the intereting part.
CDMA still retains certain "land line legacies" one of which is the
fact that when
you use it you have to use a 'dialer' in order to get a path, now once you have
established your 'connection' the radio side if it is idle to long
will hang up, as
soon as you do some activity that causes it to need to send data to the network
in the background the dialer 'redials' the link and brings up the
path. This usually
only takes 4-8 seconds so you may or may not perceive a delay when you start
doing what you are doing. BUT if the network is busy and there is not
a available
resource you may get a 'busy' When we do CDMA testing we use two computers,
one gathers RF environmental data, and at the same tiime pings a remote server
and gathers round trip time data, and the second one does nothing but set there
and ever 45 seconds (that is the industry standard for this test) attempt to get
'dialtone' which is just a digital confirmation that the path is
there, if we get it
we log the 6 different code returns calculate the time it took to get
DT and then
hang up. If after 45 seconds we get no DT we capture all of the error codes
and hang up and start again.
They appear to do this in order to conserve RF facilities, I see no other reason
to do so.
GPRS/EDGE on the other hand looks like a NIC card, when you turn the device
on it sticks up it's hand and registers with the network, the network checks the
registration (are you a paid subscriber and are you up to date?) and if all is
OK registers you, there is no dialer, no delays unless you have moved into a
poor coverage area then you may see delays due to retries or deep FEC for
error recovery, but if there is a reasonable path there will not be any delays
trying to establish a new circuit.
If the site is loaded you may see delays due to high traffic loading and retries
but I have yet to see that on a GPRS site, not saying that it does not happen.
The disconnected mode of GPRS/EDGE seems to facilitate getting a packet
through here and there on a loaded network much better than the 'dialer'
concept of checking if the full resource is available.
You need to compare them in terms of where you are going to be traveling,
if you do international then GPRS/EDGE is what you need as that is what is
used in much of the rest of the world.
Verizon has very good coverage in much of the country and if you keep the
machine busy you will not notice the 'hangups' much.
Will be interesting to see what happens after Cingular and ATT WS merge,
both of them are rolling out EDGE and will have a even larger combined
network.
Both Verizon and AT&T provide you with a "all you can push down the pipe"
price of right around $75/mo. You need to check out the different plans and
see which one works.
We use the Sierra Wireless cards exclusivly at work, and indeed I think they
are the only product has Linux support though it is third party and they do not
support it directly.
Here is a SW555 card (the card that Verizon uses) page
ttp://centerclick.org/aircard555/
Here is a page for the 7x0 series cards (GPRS)
http://www.sierrawireless.com/SupportDownload/ac7x0_linux.asp
A google will turn up a lot of data.
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