Symbol PTC-2124, Руководство пользователя, Страница: 105 / 114

PTC-2124 User’s Guide 93
resume
A feature of the PTC that returns you to the point at
which you were in your application program when the
PTC entered a reduced power state. See reduced
power state.
RF
Radio frequency.
RI
Ring indicate signal. RI alerts a modem to a call
waiting on the attached telephone line.
ROM
Read-only memory. In the PTC-2124, ROM stores the
PTC’s BIOS.
RS-232
An Electronic Industries Association (EIA) standard
that defines the connector, connector pins, and signals
used to transfer data serially from one device to
another.
RTS
Request-to-send signal. RTS initiates the data
transmission sequence on a communication line
between a modem and a terminal device.
RXD
Receive data signal. RXD indicates that a device is
currently receiving data.
signals
Electronic impulses that transmit data from one
device to another.
software
A stored program or set of programs that is loaded
into RAM for execution. Contrast with hardware.
Software Development Kit
A set of diskettes containing libraries of C programs
and Symbol utilities to be used for programming pen-
based applications for the PTC.
spread spectrum
A radio communication technology that distributes an
RF signal over a wide range of frequencies for
transmission; it then “de-spreads” the signal to the
original frequency range at the receiver.
stylus
A passive pointing device shaped like a writing pen. It
allows commands and data to be entered by touching
or writing directly on the PTC’s screen.