Text 218, 126 rader
Skriven 2004-07-30 00:31:15 av Roy Witt (1:10/22)
     Kommentar till en text av Michiel van der Vlist (2:280/5555)
Ärende: Fido on the move via cell phone.
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06 Jul 04 11:03, Michiel van der Vlist wrote to Roy Witt:


 >>  MvdV> Problem is that having a phone with a Dutch SIM work
 >>  MvdV> in Germany is not a national, but an international issue.

 >> What is this SIM you guys keep talking about?

 MvdV> It is an acronym for Subscriber Identity Module. The early models
 MvdV> were the size of a credit card, now they are 25 x 15 mm.

Hmmm, about the size of the picture card in my digital camera.

 MvdV> Rh chip contains the information needed to identify the customer to
 MvdV> the network. Most important: the IMSI. International Mobile
 MvdV> Subscriber Identity number. Plus the necesary passwords. There is
 MvdV> also some 32k of flash memory on the chip to store user data. Such
 MvdV> as the private telephone book and other things.

I have no idea of the size of the memory chip in my cell phone, but it
will store over 130 phone numbers, voice recognition id and email
address.

 >> There's no such thing here, that I'm aware of.  There's no removable
 >> card in the cell phones I've looked at; only way to change them is
 >> to hook them up to a computer and let the software do the work.

 MvdV> The idea of the SIM comes with the GSM system. A GSM phone without
 MvdV> a (valid) SIM can be used to make a call to 112, but that is all.

The same here, with a phone that isn't assigned an phone number and a
user id. Here, that is written into memory by the seller.

 MvdV> When the phone break, you buy a new phone, insert your SIM amd
 MvdV> there you go. When you lose the SIM, your provider will give you a
 MvdV> new SIM with the IMSI coupled to your old phone number. Unless it
 MvdV> is an anonymous prepaid of course, as in that case you can not
 MvdV> prove that the phone number is yours.

Here, the phone number is yours and may be taken with you to a different
provider if you wish to change.

 >>  MvdV> It is the same as expecting your US phone to work in Mexico.

 >> As I live so close to Mexico, that's not even an issue.
 >> They work there.

 MvdV> If your provider has a roaming agreement with one or more Mexican
 MvdV> providers.

Actually, my provider, Verizon Wireless, is probably the same provider in
Mexico.

 >> Probably not 'deep' into Mexico, but that would be because
 >> the cell sites aren't there, not because the service doesn't go there.

 >>  MvdV> It may work or it may not. If you just bought a
 >>  MvdV> cell phone of the shelf at St Diego international
 >>  MvdV> airport, how big is the chance it works in Mexico?

 >> Probably very good.

 MvdV> Even if it is a prepaid?

As long as the prepaid provider offers service in Mexico.

 MvdV> Could I - as a non US resident - get a phone with a subscription at
 MvdV> San Diego airport?

Yes. I wouldn't do it there, but it can be done by walking up to a
wireless provider's kiosk and subscribing to their service. They'll
probably provide you with a new phone at no cost with a two year contract
(costs more without a contract) and program the phone with a number and
your user id...once that's done, it takes about 2 hours to get the
information programmed into their system.  Nine times out of ten the phone
will be a throw-away if it's a short term contract.

 >> Those 'off the shelf' cell phones are programed to work before
 >> you get them. All they need to do is program them with the
 >> phone number when you buy it.

 MvdV> For GSM: All they need to do is insert the SIM card...

They have a computer with a cable right there at the counter and it takes
only a minute, once they have all of the information they need.

 >> If there was a problem with them not working in Mexico,
 >> you'd be notified before the purchase was finalized.

 MvdV> And if you forgot to ask, would the retailer not "forget" to tell
 MvdV> you?

You probably wouldn't need to ask, as they'd tell you up front. The idea
is to sell you a service, not just a cell phone. Any company who did,
wouldn't be in business very long. Take MCI for instance. They used other
wireless services (AT&T and others) and called them their own. When people
found out, they abandoned MCI and went with someone who could provide the
coverage that MCI advertised, but didn't have. I was one of them.  When I
had an accident that totaled my car on a rainy toll road in Kansas, the
only service I had was 911 on a Verizon cell site. Thankfully, that was
all I needed, but MCI had advertised wireless roaming throughout the
USA and it didn't work east of Las Vegas, Nevada.

 MvdV> The thing is; when you buy a phone and SIM at Schiphol airport,
 MvdV> there is a pretty good chance, it would work in Germany as well.
 MvdV> There is no guarantee though. And the retailer may indeed not tell
 MvdV> you if you don't ask. If one does not know what one is doing one
 MvdV> may end up with something that does NOT work.

It's always a good idea to ask questions when you have no idea what the
service includes or doesn't include. But, most of them will point out
certain things that you should be aware of.

 MvdV> As I mentioned before, my girl's T-Mobile prepaid did not work in
 MvdV> Luxembourg. It worked in France, Belgium and Germany, but not in
 MvdV> Luxembourg.

Cell phone service has gotten so big here, there's no place that they
don't work, as long as there's a cell site around.  In New Mexico and west
Texas, the cell sites are on 100 foot or taller towers, visible for miles.



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