Technical data

72 Theoretical and general applications www.westermo.com
V.23 on a leased line
V.23 is an old standard that initially was designed for leased lines. Data transfer rates
are standardised to 600 and 1200 baud. Modems that follow the V.23 standard usually
have at least the following functions:
… Modulation speeds up to 600 or 1200 baud.
… Frequency modulation (FSK)
Two different frequency modulations are used as follows:
… Mode 1: 600 baud 1300 Hz–1700 Hz
… Mode 2: 1200 baud 1300 Hz–2100 Hz
V.23 normally permits up to 6 drop points on a 2-wire cable. The maximum
number of modems on a line is however dependent on how the modems have been
installed, as impedance problems are common. The line impedance for V.23 should be
600 ohm.
Westermo V.23 modem
Westermo V.23 modem (TD-23) supports all speeds up to 1200 baud. It is possible to
terminate the line with a 600 ohm line resistance. All levels such as carrier, transmis-
sion and reception levels are adjustable.
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