10
Data Packets
– A grouping of data to be sent over-the-air. Each data packet contains a
header and data that is collected from the data buffer. The size of the packets varies up to
64 bytes depending on how many bytes of data are in the data buffer.
Glossary (cont.)
Frequency Hopping Spread Spectrum (FHSS)
– Method employed by the MDR210A-
485 module which involves transmitting data over several different channels in a specific
channel hopping sequence known by the transmitter and the receiver(s).
Half-duplex
– A mode for radio operations. Radios that operate in half-duplex are able
to either transmit data or receive data at a given time, but cannot do both simultaneously.
When one module is transmitting, all modules within range listen to the transmission and
will only transmit when the transmission is complete.
Module Addresses
– Provides a layer of addressing among modules. Modules with the
same Module Addresses can communicate together.
Networks
– Provides a layer above Module Addresses for communicating between
modules. Each network has a unique hopping sequence that allows modules on the same
network to remain synchronized together.
RS-232 logic
– Standard logic levels implemented in devices using the RS-232
communication protocol.
Sensitivity
– A measurement specification that describes how weak a signal can be
(in dBm) and still be detected by the receiver.
Serial Data
– Data that enters the MDR210A-485 module through its serial port.
Start bit
– A low UART signal to signify the beginning of an eight-bit data sequence.
Stop bit
– The last bit in a UART data sequence. The stop bit is high and indicates the
end of an eight-bit data sequence.
Synchronization
– Synchronization is used to ensure that the transmitter and receiver are
communicating properly with each other and following the same channel hopping
sequence.
Transmission Latency
– Time required to send a packet of data. This value is
dependent on the number of bytes being sent and the baud rate of the module.
Transmit Mode
– Mode of operation in which over-the-air data can be transmitted from
a module to other modules.
