Telecommunications, also mentioned as telecom, is that the exchange of knowledge over significant distances by electronic means and refers to all or any or any kinds of voice, data and video transmission. This is often often a broad term that features a good range of knowledge transmitting technologies like telephones (wired and wireless), microwave communications, fiber optics, satellites, radio and television broadcasting, the online and telegraphs. An entire, single telecommunications circuit consists of two stations, each equipped with a transmitter and a receiver. The transmitter and receiver at any station could even be combined into one device called a transceiver. The medium of signal transmission are often via electrical wire or cable (also mentioned as "copper"), optical fiber , electromagnetic fields or light. The free space transmission and reception of data by means of electromagnetic fields is known as wireless communications. The sole kind of telecommunications takes place between two stations, but it's normal for multiple transmitting and receiving stations to exchange data among themselves. Such a meeting is known as a telecommunications network. The online is that the most important example of a telecommunications network. Data is transmitted during a telecommunications circuit by means of an electrical signal called the carrier or the carrier. So as for a carrier to convey information, some kind of modulation is required. The modes of modulation are often broadly categorized as either analog or digital.