
What is the difference between a Router and a Modem???
Routers and modems are two of the most common computer peripherals, yet many people don’t know the function of each one. While the two devices may look similar, they each serve a difference purpose. Fortunately, the functions of the two devices are pretty easy to understand.
Modem:

A modem is a device that provides access to the Internet.
The modem connects to your ISP, which typically provides either cable or DSL Internet service. Cable modems have a coaxial (or “coax”) connection, which is the same type of connector found on a TV or cable box. This connects to a cable port on the wall. DSL modems have a telephone connector, also called an RJ-11 jack, which connects to a telephone socket on the wall.
By connecting your modem to your router (instead of directly to a computer), all devices connected to the router can access the modem, and therefore, the Internet. The router provides a local IP address to each connected device, but they will all have the same external IP address, which is assigned by your ISP.
To summarize, the device connection order is outlined below:
PC or wireless device.
Router.
Modem.
ISP.
Internet.
While the router and modem are usually separate entities, in some cases, the modem and router may be combined into a single device. This type of hybrid device is sometimes offered by ISPs to simplify the setup process.
Modem (Modulator Demodulator) is a device that transmits a digital signal over an analog carrier. Its main purpose is modulation of an Analog Signal -> Digital Signal and vice-versa,
A router is a device that is used to connect networks with different subnets.
Now depending upon your own knowledge, you might/might not understand this, but the above two sentences sum up all of the story.
Gong with the ‘might not’ case, here is the full story.
Do you recall (regarding if you are old enough) that the only way to connect to the Internet was using a device installed into the bare-bone of your desktop? You had to connect a telephone wire to it and whenever you ‘dialed’ to the internet, it would make very annoying noises.
That device was a MODEM.
Everything that has a microprocessor in it is in fact digital. Hence when we want to access the internet, or any data in the globe we need to go digital. But since digital signals and analog signals are extremely different in nature, there has to exist a sort of a media converter.
I have to point out that media converter is actually a very incorrect term. I just used it so the purpose of the modem could be clarified. A modem is not a media converter. It is a modulation device, hence referred to as MODEM.
Regarding what is Modulation, it is a process by which a digital signal is super-imposed upon an analog carrier. This is done so that the digital signal would make it to the other side with minimal degradation.
A question arises that why just don’t we shove the digital signal into the wire and pray that it gets where it want to go? If you plan on living under 100 meters from the telephone exchange, then yes, why not…
Since this is evidently not possible, and hence also the reason why modulation is required. Modulation makes it possible for the digital signal to go further.
Now that we have a modulated signal, how do we extract the digital signal from the modulated one? We use a demodulator.
Since internet communication is a very to and from communication, we need a Modulator and a Demodulator incorporated into the same device so we can establish a proper and prolonged connection, hence MODEM.
Router:
