Text 282, 148 rader
Skriven 2004-08-02 12:24:00 av Michiel van der Vlist (2:280/5555)
    Kommentar till text 218 av Roy Witt (1:10/22)
Ärende: Fido on the move via cell phone.
========================================
 >  MvdV> It is an acronym for Subscriber Identity Module. The
 >  MvdV> early models were the size of a credit card, now they
 >  MvdV> are 25 x 15 mm.

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

A bit thinner perhaps. The SIM is only as thick as a credit card.

 >  MvdV> The idea of the SIM comes with the GSM system. A GSM
 >  MvdV> phone without a (valid) SIM can be used to make a
 >  MvdV> 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.

The strong point of the use of a SIM is enhanced security. Your phone can be
cloned, a SIM can not. The protected memory area of the SIM can not be read or
written to after the one time protect bit is set. Passwords are verified by a
query/response system. So only the provider and no one else knows the passwords
ect.

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

Same here.

But of course you must be able to show that the numvber is actually yours.
Either by showing posession of the SIM or by having it registered beforehand.
If you buy an anonymous prepaid and do not register it, you can not show that
you are the legal owner of the number when you lose the SIM.

 > >>  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
 >  MvdV> more Mexican providers.

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

Looks can be deceptive...

 >  MvdV> Could I - as a non US resident - get a phone with a
 >  MvdV> subscription at 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

What guarantee do they have that I live up to my part of the contract? If i
just take the next plane back to The Netherlands how are they going to collect
from me?

 > >> 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 they can do it, you can do it...

 > >> 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
 >  Mvd> "forget" to tell 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.

Also if they sensed I am a foreigner and unlikely to ever come back?

 > 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.

Of course, that sort of thing does not go unpunished in the long run.

 > 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.

So next time you would not buy from MCI any more. And probably tell your
friends and family to stay away from them too as they do not deliver what is
promised.

But I as a one time visitor would not be in that position.

I never believe salesman that promise all kind of things when I am not in a
position to come back and the salesman knows that I will not be able to come
back.

 >  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.

Then one must know what the right questions are.

 > But, most of them will point out certain things that you
 > should be aware of.

If they are aware of what you should be aware of...

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

Same here. But the fact that Europe is not one country complicates things.

 > In New Mexico and west Texas, the cell sites are on 100 foot
 > or taller towers, visible for miles.

They usd to be that big here too, but with the growth of ythe networks cell
sizes have become smaller and smaller and now one has a hard time spotting the
antennas in congested areas as they are often hidden in existing structures
such as McDonalds big "M". ;-)

Cheers, Michiel

--- InterMail 229kx
 * Origin: If privacy is outlawed, only outlaws have privacy. (2:280/5555)