Modem - Modulator/demodulator

• Device that encodes and decodes data by manipulating the carrier wave

• V-series of modem standards (by ITU-T)

  • V.22
    • An early standard, now obsolete
    • Used FM, with 2400 symbols/sec ? 2400 bps bit rate
  • V.34
    • One of the robust V standards
    • Used TCM (8.4 bits/symbol), with 3,428 symbols/sec
      ? multiple data rates(up to 28.8 kbps)
    • Includes a handshaking sequence that tests the circuit and determines the optimum data rate

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