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causing the bits to “retain” the pattern as it is “burned in.”
Firmware is nonvolatile. It will not be “forgotten” when
the power is shut off. Handheld calculators contain
firmware with the instructions for doing their various
mathematical operations. Firmware programs can be
altered. An EPROM is typically erased by using intense
ultraviolet light.
Grayscale. Not a level of resolution, but a method of
scanning and transmitting halftone images. Fax machines
with grayscale abilities interpret photographs in levels of
gray between white and black. The transmitting fax machine
must have grayscale ability to send a photographic image
accurately, but the receiving machine does not need it to
print the image.
Group 3. Refers to fax machines that use digital encoding.
These units transmit one page in less than one minute and
produce resolution of 203 x 98, 203 x 196, or 203 x 392 lpi.
Group Dial. Sending one fax to multiple locations.
Document is scanned once, then transmitted to multiple
locations using a combined list (group) of programmed
numbers. Different from relay broadcasting, where one fax is
sent to a remote machine. The remote machine then relays the
fax to a group of fax numbers.
Halftone. See Grayscale.
Handshaking. A data interchange between
telecommunications and/or computer equipment that
“introduces” two systems to each other. For example, faxes
use a handshaking protocol to identify the ITU-T group of
each unit and to begin fax communication.
Hub. See Relay broadcasting.
Hz (or Hertz). A measure of frequency equal to one cycle per
second. Used in the specifications for a fax machine, it
identifies the AC power the unit requires.
ITU-T. International Telecommunications Union —
Telecommunications Sector. (Formerly known as CCITT, for
Consultative Committee for International Telegraph and
Telephone.) A telecommunications forum for member
countries of the United Nations; its Study Group XIV
established the primary groups for fax equipment, covering
communication protocol and transmission.