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- The term cellular internet
encompasses all smartphone,

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and some tablet, internet
connectivity made

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via the connection to the
carrier, to your provider

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as opposed to a wifi connection.

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And this all began with 2G:

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the old school 2G speeds
through your cellular network.

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And there's a couple options with this.

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GSM, the Global System
for Mobile Communications,

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is very common if you
have AT&T or T-Mobile.

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They would use GSM to
make the voice calls,

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and then the general packet
radio service, or GPRS,

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to send data through
that cellular network.

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If you have another provider,

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like Sprint, or Verizon, or US Cellular,

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you'd use CDMA to send the data,

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and that's Code Division
Multiple Access technology.

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So two different options there,

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but basically 2G is too slow.

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If you wanna watch video or send photos,

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2G's not gonna cut it.

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So there are extensions to these services

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which are used in most
parts of the world now.

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First of all, 2G evolved into 3G

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with enhanced data
rates for GSM evolution,

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that's known as EDGE.

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And then in many areas you
can now get 4G and LTE,

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as long as the mobile device complies

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with the International
Mobile Telecommunications

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advanced requirements, the
IMT advanced requirements.

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And that means it has to have a 4G antenna

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and it has to be in range
of a 4G transmitter.

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Most devices manufactured
during this video,

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during the time of the
recording of this video,

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are 4G with LTE. And so you can get speeds

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of upwards of 50 to 100
megabits per second,

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you know, depending on your connection.

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Typically I'll get about
30 megabits per second,

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and I'm pretty close to a radio tower

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and that's a 4G LTE connection.

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5g is also available in some areas

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at 20 gigabits per second,

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standardized as ITU IMT-2020.

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Let's show a mobile device now

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and show the actual connectivity

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in the about section for the device

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and show how it connects
to the cell phone tower.

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So here we have a Galaxy
Note and you can see

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at the top here that the wireless is on

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and that's important, if the wifi is on,

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that's gonna change what we
see in our network settings,

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but I'm in the settings right now,

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and I'm gonna go to About Device,

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and then from there, go to status,

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and then you see the network
we're on is T-Mobile,

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and we see mobile network type is iWLAN,

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well WLAN means wireless
local area network.

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That means that that's
the wifi connection.

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So in order to see

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the actual network we're
using for cellular,

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I have to turn off the wifi.

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So we'll go to the, swipe down

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to the notification area,

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turn off wifi, swipe back up

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and then you see it has changed to LTE.

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So I have an LTE connection for 4G

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and it's at -107 DBM,
which is a good connection

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as I mentioned, real
close to the cell tower.

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So it gets a pretty powerful connection.

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And if we swipe back down,
turn the wifi back on,

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because we definitely want wifi.

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And we see that the mobile network type

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changes back to iWLAN.

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So, normally you'd go to the settings

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and go to about and you might also

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have to go to status
within the about section

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to see what network you're connecting to

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and how good the signal is.

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Okay. Let's talk about
updates a little bit.

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First PRL updates, that stands
for Preferred Roaming List.

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And it's used by cellular providers

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that are working with CDMA technology.

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So Sprint, Verizon, US cellular,

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they're using CDMA instead of GSM,

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they're gonna use these PRL updates.

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And what that is is a database

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that contains information about
the providers' radio bands,

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sub bands, service providers' IDs.

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Ultimately it allows the phone

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to connect to the correct tower.

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Without this database of information,

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you might not be able
to connect correctly.

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You might not be able to
roam outside the network.

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And so, when necessary,

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the PRL updates are sent over the air.

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However, you can also update this

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by manually dialing a special number,

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which is different for each provider.

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Now, if your phone uses
GSM, then that technology

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and its radio functions
are controlled by a chip

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and software collectively
referred to as baseband

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and baseband updates are
necessary to communicate

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with the GSM cell towers.

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So it's the same type of thing.

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You know, basically,
your PRL updates are used

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by CDMA devices.

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Your baseband updates
are used by GSM devices.

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Now next on the list
we have, IMEI and IMSI.

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These are both
identification technologies.

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IMEI stands for

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International Mobile
Station Equipment Identity

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and it'll identify phones used

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on GSM or UMTS or LTE networks.

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It can often find this ID
number printed inside the phone

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on the battery or near the battery.

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And it's only used to identify the device.

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You can also find this

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in the about section on the phone.

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So once again, we're
at our smartphone here,

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we're in the settings.

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If we go to about device

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and then go to status

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and scroll up a little bit,

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we'll see the IMEI setting
right there, there's our ID.

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And so that identifies
this individual phone

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to the provider and also to
any authorities if necessary.

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And IMSI or IMSI

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is the International
Mobile Subscriber Identity.

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So this is used to identify the user.

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For GSM networks, this ID
is loaded into a SIM card,

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a Subscriber Identity Module card.

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For CDMA networks, the ID
is either loaded directly

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into the phone storage

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or to a Removable User
Identity Module, RUIM,

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which is similar to a SIM card.

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So you wanna know about the IMEI

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which identifies the phone or the device

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and IMSI, which identifies the user.