User's Manual

Page 178 FRH-SD07TU/TB Manual
transmitted as a single unit or packet of data. Each transmission is controlled with
explicit transmit commands.
- and Contention-type Communication Polling
he polling is a type of communication, where the slave station can communicate
ication, where any station may transmit if
nel is free; if the channel is in use, the queue of contention request may be
Repeat
signals and retransmits the same data in stronger
Used to extend range or overcome obstacles and horizon constraints in RF
can be configured as a repeater to
Respon
r the value
pplication.
owever, it must be noted that the response is not always quick when the throughput
RS-232
RTS, o
Spread
n technique that spreads data over an RF bandwidth wider than would
Hopping and Direct Sequence. See also Direct Sequence and
T
only when it receives the polling request of message data from the master station.
The contention is another type of commun
the chan
maintained in the predetermined sequence.
er
Equipment that receives weak
signals.
communication systems. An FRH-SD07TU/TB
effectively double the normal range between two FRH modems or to allow
communication around obstacles that would otherwise block line-of-sight
transmission.
se
One of the values to express the communication speed, indicating the time delay
required by the transmitted data to reach the receiving modem. The smalle
becomes, the quicker the response requiring the machine control a
H
is large.
C
Also referred to as RS-232C and currently EIA-232E, RS-232C is a set of standards
specifying electrical, functional and mechanical interfaces for communicating
between computers, terminal equipments and modems (DTE and DCE).
r Request To Send
In the standard RS-232C interface, this is an output for DTE devices and an input for
DCE devices. This signal is typically used to control flow from the DCE to the DTE
device.
Spectrum
A modulatio
normally be required by the content of the original data stream. This technique
provides high levels of communication reliability and security. In the modulation
system generally used for radio, the bandwidth is about the same as the frequency of
the data signal. But in the spread spectrum system, the bandwidth is much wider than
the frequency of the data signal (tens to several thousands times), in other word, the
spectrum of the data signal can be spread in a broad range, thus this system is called
the spread spectrum (SS).
i.e. Frequency
Frequency Hopping.
Rev. 050415-01.1