What Is Modem?


Modem is a device that can transmit data for long-range. The modem is a network device which is mainly used to access internet network but can be also used different special network access. The modem name is created with the conjunction of “Modulator” and “Demodulator” words which are two fundamental functions of a Modem.

Modem History

The first modem is used to multiplex lines in the 1920s for “News wire services”. Mass production of modems is started with the “SAGE” modems which are used for air-defense systems in 1958. Bell created a 103A dataset standard in 1962 which can work 300bit/s over a normal phone line. As a telecommunication company and monopoly, Bell created a lot of modems and created standards during the 1960s.In 1972 Vadiac introduced the VA3400 modem which can work full-duplex at 1,200bits/s over a phone network. The modern modem area starts in the early 1980s where speeds up to 18,432 bit/s were supported. Then 28.8k modems with 2400 baud rates are developed in 1994. Modems were mostly used for the internet connection and there were alternative ways to connect the internet. Last modems create with 33.6k and 56k speed later 1990s a.

Modem History

How Modem Works?

Modems work over analog phone lines in most of the cases. But computers and computer networks are completely digital. So the computer network data is digital and can not be transferred over the telephone lines by default. A modem that contains modulator and demodulator components translates digital data into analog signals which can be transferred over analog phone lines. Also modem can demodulate analog signals coming from the phone line into digital data. The internet connection is provided by the ISPs where the modem will connect to the ISP POP (Point Of Presence) point and the POP point has internet connection via fiber or cable.

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Modem Types

There are different type of modems which are mainly related to the connection type and technology.

Cable Modem will use coaxial cables in order to transmit data. Coaxial cables are also used for antennas. The cable modem connection is the most reliable modem connection but creating the infrastructure is expensive for the ISP.

Cable Modem

DSL Modems are the most popular modem types in today’s world. DSL modems generally named as ADSL modems because the download speeds are higher than the upload speed. DSL modems use the telephone lines which is very widespread and cheap to operate for ISP.

DSL Modem

Dial-up Modems are similar to the DSL Modems but they are the predecessor of the DSL Modems and provides low speeds. If the dial-up modem is connected the phone can not be used or while using a phone dial-up modem can not connect to the internet.

Dial-up Modem

Modem Advantages

Modem became so popular during the 1990s and 2000s because of its huge advantages. Let’s list some of the most important advantages of the Modem.

  • Modem connection and internet access are very cheap.
  • Modems generally use phone lines that are already available.
  • The modem may provide high speeds with advanced modem types and good connections.
  • The modem is the most common connection type especially in rural areas.

How To Chose Modem?

Modems are currently very cheap with mass production. If we need to buy a modem for using at home or at work we need to take care of the features and some metrics of the modem.

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Internet Infrastructure: First, we should check the currently available internet infrastructure. Mainly cable, dial-up, and ADSL connections are provided. We can use the following precedence if available.

  1. Cable Connection
  2. ADSL Connection
  3. Dial-up Connection

Modem Type : We will select the modem type according to the connection type. If the connection type is cable or coaxial we should select a cable modem that supports DOCSIS protocol. If it is an ADSL connection we should select an ADSL modem with proper ADSL versions like adsl+, adslv2.

Compatibility: For cable and ADSL modems the ethernet can be used to connect the internet but dial-up modems the dial-up modem should provide an interface like USB, PCI to connect the computer directly.

Speed : Speed is another important factor where dial-up provides very low speeds. Adsl and cable connections provide higher speeds around 20-30 Mbps. Also in most cases the download and upload speed will be asymmetric which means download speed will be a lot higher than upload speed.

Modem vs Router

Even modem and router are different devices providing different services they can be used interchangeable because of the ADSL Routers functions. The router is mainly responsible for routing network or internet traffic between different networks. Modems generally provide the routing functions in order to reduce expense and operation const simply they can be called as “ADSL Modem”, “Router, “ADSL Router” interchangeably.

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