Cellular technology.
We now want to dive into the key identifiers on GSM and CDMA,
and how they are similar and also how they are different.
Let's start with the serial number.
Now, the serial number for GSM and CDMA
can often be found under the battery on the device.
But you're going to come across some devices
where you can't remove the battery,
so you may have to find this in the settings.
IMEI is the serial number for GSM devices.
This stands for International mobile equipment identifier,
and it's a 15-digit number.
For CDMA, there are two options.
The first is the electronic serial number, which is ESN.
This could be 11 digits in decimal or 8 digits in hex.
So make sure you know the difference.
The hex should stand out to you when
you look at this identifier.
You'll find some settings will translate it into both,
or decode both, and show you decimal and hex.
For MEID, this is the mobile equipment ID.
And it replaced ESN.
This is a 56-bit number that is available on CDMA handsets.
The phone number is commonly one of the hardest
things we have to do and find in smartphone forensics.
MS ISDN.
This is the phone number that is found on GSM devices,
and this stands for mobile station
international subscriber directory number.
It's 15 digits in length, and it's a globally unique number.
For CDMA, we have MDN, which is the mobile device number.
These two will tell you, as a huge clue,
if you're dealing with a CDMA handset or GSM device.
Keep in mind, in the next slide, we're
going to talk about SIM cards.
The SIM card may provide you with the MSA--
MS ISDN-- sorry about that--
or MDM.
So keep that in mind.
For IMSI or MIN, when we look at these identifiers.
This is how the network knows who you are when
you attempt to use that phone.
IMSI is going to be for GSM, and MIN,
or the mobile identification number,
is going to be for CDMA.
And again, this is how you are identified.
When you go to make a call on that phone
or you go to leverage an application on that device,
it is how your network service provider knows that it is you,
that you have a data plan, that your prepaid plan is
up to speed, or if you need to add minutes.
All of these technology terminologies matter.
Make sure you know them.
Make sure you reference them.
It is rare that people memorize what these acronyms mean.
Use this page in your book as a reference going forward
in your examinations.