56k modems are voiceband In electronics, voiceband means the typical human hearing frequency range that is from 20 Hz to 20 kHz. In telephony, it means the frequency range normally transmitted by a telephone line, generally about 200–3600 Hz. Frequency-division multiplexing in telephony normally uses 4 kHz carrier spacing. The rate at which the amplitude of a signal modems A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used over any means of transmitting analog nominally capable of download speeds up to 56 kbit/s (56,000 bits per second). At the beginning of the 21st Century, most personal computers contained one, but their use is declining as broadband technologies such as DSL DSL or xDSL is a family of technologies that provides digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop, but as of 2009[update] the term digital subscriber line has been widely adopted as a more marketing-friendly term for Asymmetric Digital Subscriber Line , the most popular gain wider availability.
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