Black Box 5000 - Manual (Page 265)

Glossary
263
VF, voice frequency — Any frequency within that
part of the audio-frequency range essential for
the transmission of speech of commercial
quality (300-3000 Hz). This is the frequency
range used over telephone lines.
voice compression — A method of minimizing
bandwidth by reducing the number of bits
required to transmit voice.
warm start — A system reset that maintains the
current configuration. A Multiserver warm start
may be performed in the Command Facility or
at the front of the unit.
X-ON, X-OFF — Control characters used for flow
control.
X.21 bis link — Commonly used in European
countries, this is a pay-as-you-go link. When a
signal is raised, the network automatically
establishes a link to the remote unit. This link is
utilized for Multiserver-to-feeder mux
connections.