PictureTel Concorde 4500 Servicing Manual page 208

Dual-Tone Multiple Frequency (DTMF)
The scheme for encoding digits with audible sounds used by TouchTone push-button
telephones.
echo canceler disable tone
A tone to disable voice echo suppression equipment used on networks that do not separate
data and voice trafÞc.
EIA RS-232
An EIA (Electronics Industries Association) serial interfacing standard for connecting
terminals, modems, and serial printers.
EIA RS-449
Generic 37-pin differential data interface; +/- 5 volts.
Electronics Industries Association (EIA)
A standards organization in the United States that specializes in the electrical and functional
characteristics of interface equipment.
field replaceable unit (FRU)
Any component or group of components within a system that can be replaced by a Þeld
service representative.
high-speed data port
A data port on the IMX that connects to PictureTel equipment and supports data rates of only
56 or 64 kbps.
IMUX port
A data port on the IMX that connects to PictureTel equipment and supports data rates of
Nx56 or Nx64 kpbs (56 to 366 kbps or 64 to 384 kpbs). These ports provide inverse
multiplexing.
IMX
A family of devices that provides switched digital network access for PictureTel
videoconferencing systems and M-8000™ multipoint bridges.
inband signaling
Signaling made up of tones which pass within the voice frequency band and are carried
along the same circuit as the talk path that is being established by the signals.
integrated dynamic echo cancellation (IDEC)
A PictureTel proprietary audio standard which virtually eliminates echo while enabling full
duplex video.
Glossary-4