What is Modem
Definition: MODEM full form is “Modulator-Demodulator” that means it has ability to modulates and demodulates analog carrier signals for encoding and decoding digital data for executing. Modem is a hardware networking device that helps to make connection with computer or other hardware components like as switch or router for linking to internet.
Purpose of Modem
Modems are used for performing both activities like as sending and receiving of the digital data in between with multiple computer systems. Then this data is transmitted over the telephone lines with using V.92, to analog modems which helping out for converting those signals back to digital form for readable format to computer.
Modem plays role as digital translator that helps to get all information signals from cable, fiber or telephone line and convert it into accessible form for your PCs.
Types of Modem
There are different types of modem which are used in computer networking; below explain each one –
Dial-up Modem: Dial-up modems transmits analog signal via telephone lines. This modem is uses mostly to make connection with ISP using of analog signals. Dial-up modem has two variant like as external or internal modem.
Cable Modem: In the cable modem, to use the coaxial cables those are connected to the back edge of modem.
ADSL Modem: ADSL stands for “Asymmetric Digital Subscriber Line” and these types of modems uses the telephone line for sending and receiving all information. ASDL modems have higher speed compare to conventional voice and modem.
ASDL modem uses two types of data transmission methods like as “Synchronous and Asynchronous“. Synchronous transmission is used into more accurate for your timing signals but asynchronous transmission is used into mistaken correcting formulas.
DSL Modem: DSL stands for “Digital Subscriber Line“, and it is also known as “Broadband Modem“. DSL modems offer broadband services for using of different types of internet connections. DSL modems are comfortable for higher internet speed.
External Modem: External modem likes as standalone modem because it doesn’t integrate any router. This modem is connected with the computer through USB stick, WIFI or Ethernet cable. It has option for getting connection with separate router, if you want to share make connection with several network terminals around small zone.
Router/Modem Combo: This type of modem is contained with router that allows several devices and computers to attach within single network. So, users do not require a extra router and modem.
Integrated Modem: This modem is embedded into computer in the form of USB or PCI card. But, this type of modem allows only single computer system to make connection with internet.
Onboard Modem: Onboard modems are embedded onto motherboard, so this modem has not any chance for removing, but it can be disable with using of jumper or BIOS setup.
Removable Modem: This modem can be inserted or removed as per the requirement, and these modems are used into traditional laptops PCMCIA slot.
Wireless Modem: Wireless Modem is also known as “Radiofrequency Modem“, and these modems are developed to work with cellular technology and wireless local area networks.
Fax Modem: Fax modem is used for transmitting and receiving any document over the telephone line, and this modem works like as fax machine.
ISDN Modem: ISDN stands for “Integrated Services Digital Network“, and it provides to make communication standards for using of digital transmission of voice, video data over wire or optical fiber.
Intelligent Modems: Intelligent Modems are more costly to other modem because it is able to diagnostic error checking within the modem itself. This modem consists internal read only memory (ROM) coding and microprocessor chips to offer sophisticated communications protocols.
Functions of Modem
Here, we will explain various functions of modem in computer networking, such as –
Data Compression: To decrease the amount of time when it try to send data and for cutting down on the percentages of errors in the all flowing of signals, then modem required the data compression mechanism. So, this data compression method helps to reduce the size of signals, which are required for sending data. .
Error Correction: In the error correction techniques, all devices monitor all information while receiving is undamaged. It splits all information into small units that is called the “Frames“. In this process, it tags all frames along with checksums, but it is done before sending information. Checksum is a special technique that helps to check redundancy in the presented data in the computer. If, this information matches with checksums then device grabs the verified information. That is sent by error-correcting modem. But, if it gets to fail in matching with checksum then information is moved back.
Modulate Signals: The main function of modem is to transmit and decode all signals which allow sending digital data from one node to other nodes without getting any damage of information.
Flow Control: Each modem has different speed of sending signals. so, it can generate issues during to receive signals if any one device’s speed down of them. So, in the flow control technique, slower one signals the faster one to pause, by sending a ‘character’. If, slow device will try to send character to faster modem, then this character would be a signal to the faster modem for Pausing the information transfer until the slow modem gets caught up.
Other important functions are:
- To modify the digital data such as (0s and 1s) into accurate analog signals
- Help to line control and signaling to other edges of phone line.
- If, modems are made to dial up then it can send dialing signal without knowing of users.
- Help to provide security while line overloading and other issues.
Uses of Modem
Modems are used in different areas; like as
Point of Sale (PoS): Today, every consumer try to pay through debit card, credit card or net-banking where modem plays major role in the behind with data transferring as well as returning an approval.
- ATM Machine
- Shop Online with net-banking
- Use for ticket machine in airport, bus station, and railway station
- Pay bill via credit or debit card in PVR, hotels or shopping mall.
Remote Management, Maintenance, and Logistics: Modems are installed in to remote areas at off site locations tight enclosures, or inside sensitive locations. Due this process, those applications can be managed without place boundation and not need to visit to certain location. So, it can save money and time in travel costs.
- Gas/Petrol station maintenance
- Grocery Store Freezer and Cooler Call Center
- Roadside Digital Signs
- Vending machine inventory and status
- Stoplight Timing Control
- Golf Course Irrigation system
Out of Band Access, Broadband & Server backup: Many small and large scale companies trust on the broadband connectivity for their employees for making communication with each others. So, here need trust able backup while getting down speed of broadband or server connections, it is known as “Out of Band Access“.
- Backup for ADSL connections in DVD rental or car washes
- Server backup
- Backup for VPN dial in connections
Data Transfers: Many large scale organizations have main head office location where to send data every day from all their franchise. So, it needs reliable transfer data with protective connections.
- Daily Sales data move to a headquarter
- Make synchronization of data at a headquarter location from other branches
Machine to Machine: It helps to make communication in between two machines for transfer data without any interaction of users.
- Medical devices help to move patient test report to doctor’s PC.
Other Uses of Modem are:
- Home security monitoring
- Property listings
- Cinema screening approval
- Cell phone tower maintenance
- Gasoline vapor containment system