Text 30259, 118 rader
Skriven 2009-03-24 19:51:24 av Robert Bashe (2:2448/44)
  Kommentar till text 30209 av Michiel van der Vlist (2:280/5555)
Ärende: Reactions
=================
Michiel van der Vlist wrote to Robert Bashe on Tuesday March 24 2009 at 01:31:

MV>>> Yesm the IMEI can be used for identifying and blocking stolen
MV>>> phones. That is in the GSM specs. But it is NOT used for the normal
MV>>> handling of calls and therefore not "necessarily" transmitted as you
MV>>> stated...

RB>> So how do these two statements of yours agree?

MV> You have to go back to your original remark that I commeted on:

RB>>>> All the cell phones I know of have what they call an IMEI, which is
RB>>>> the serial number of the phone, and is necessarily transmitted
RB>>>> along with the conversation since a relay station has to be able to
RB>>>> properly direct hundreds or even thousands of calls simultaneously.

MV> Note that I commented on the "to be able to properly direct.." part

I _do_ wish you'd quote what you are commenting on and not something else,
then. It's very confusing trying to decide what you're talking about otherwise.

RB>> The IMEI is transmitted at least in the handshake, which is necessary
RB>> to even start a transmission.

MV> Yes, the handshake is necessary....

RB>>  But it is not "necessarily" transmitted?

MV> The IMEI is not necessary information to set up or maintain the call.
MV> It is transmitted along with other information, but nothing is "done"
MV> with it. Any number will do, presumably including zero.

RB>> It has to be one OR the nother, not both.

MV> Both. It is transmitted in the handshake, but it is not needed to make
MV> the call.

So how do you make a call without the handshake? I still don't know what you're
trying to say.

RB>> And in view of the fact that stolen phones are blocked using the IMEI
RB>> in England, I would tend to stick to what I already wrote. I never
RB>> wrote that the IMEI was _continuously_ transmitted, since that's
RB>> naturally unnecessary, but that wasn't the point.

MV> It was this part after "since" that I think is wrong:

RB>>>> and is necessarily transmitted along with the conversation since a
RB>>>> relay station has to be able to properly direct hundreds or even
RB>>>> thousands of calls simultaneously.

OK, but you DO take every word literally. Sure makes it hard to get anything
across (in _both_ directions).

MV>>> I have seen it demonstrated. It looked simple enough. Connect the
MV>>> data cable to a loptop and some mouse clicks. Just as easy as
MV>>> removing a SIM lock.

RB>> With the proper interface

MV> Nothing special, just a standard data cable.

;-))) Who told you that one? Sorry, I know better.

RB>> I've read somewhere there was a drive to store the IMEI in a
RB>> non-writeable area of the EEPROM, but don't know how dar along that
RB>> is. The fact remains, simple it's not.

MV> Simple is in the eye of the beholder. Once you know how to do it, it
MV> ius simple.

Interestingly enough, I've found that's not the case. I became intrigued with
the idea of removing supervisor passwords on Thinkpads (IBM laptops) because so
many people forget them, buy used laptops from companies with the supervisor
passwort set and then forgotten and the like.

There are people, incidently, who consider a supervisor password (SP) "theft
protection", but that's just plain wrong, as you can use a Thinkpad with a SP
set without any problems as long as you never have to change the boot order or
reset the date/time (as when the CMOS battery has to be replaced). Otherwise
you don't even notice it's there - it's NOT required to boot the machine. (If
you want to protect your data, you have to set a hard disk password, which is
nearly impossible to remove - but you can throw the HD _and_ your data away if
_you_ ever forget the password.)

At any rate, there's a website that deals with this subject, and even free
software to read out the passwords. But you have to build a simple electronic
circuit (interface) to attach to the COM port of another (host) computer to use
it, and have clips to attach to two legs of a very small SMD chip (4x4 mm, 4
legs per side). I can do this, but if you read the questions at the website,
you see that a lot of people can't even figure out how to build the interface.
A guy I know even had a friend of his etch a couple of circuit boards for the
interface, and gave me one in return for my getting the electgronic components
and assembling them. All this worked fine with me, I also tested the one I gave
him, but he still couldn't operate it and asked me afterwards to help him
remove a SP.

Knowing how in theory is nice, but without a bit of practice and experience, a
lot of people can't duplicate what others can.

RB>>>> That's the simplest part. All you need is a SIM that is registered
RB>>>> to someone else. You can get such stuff in flea markets or through
RB>>>> Ebay. Not really legal, but it's done all the time.

MV>>> Yes, but that way, you also use a different phone number.

RB>> Is that a problem when you want to make an anonymous call?

MV> I seem to have lost track of what the objective was...

The objective was a non-registered SIM, at least not one registered in your
name, and there's no reason I can think of for that to be desirable/necessary
except if you want to make an anonymous call.

Cheers, Bob

--- GoldED+/W32 1.1.5-0613
 * Origin: Jabberwocky System - 02363-56073 ISDN/V34 (2:2448/44)