Murata Electronics North America 5811M Manual Do Utilizador
© 2003 Cirronet
Incorporated
13
M-5811-0008 Rev -
3. PROTOCOL MODES
In point-to-point applications, it is generally desired that the radios operate in a transparent
mode. That is, raw unformatted data is sent from the host to the radio and is received as raw
data at the receiving end. The addressing and error detection and correction are still
performed by the radios, but it is transparent to the user application. To set up a point-to-
point network, one radio has to be set up as a base station. When the radios are powered on,
the base station will send out the synchronization signal at the beginning of each hop. The
remote will synchronize with the base and automatically request registration. Once the
remote is registered, the radios can transmit data. Protocol mode operation is available in
point-to-point mode if desired.
If the base station is to be responsible for directing data to a specific remote in point-to-
multipoint mode, the data sent to the base station by the user application must adhere to a
packet format. This allows transmissions from the base station to be directed to a specific
remote. Data received by a base station from a remote is similarly formatted to identify to
the user application the remote that sent the transmission. The remotes may still use
transparent mode without formatting to send data to the base, if desired. The WIT5811
protocol format is described in detail below. The protocol format is selected through the Set
Protocol Mode command.
Base radios can use protocol modes to insure that a packet is transmitted to the base without
being broken up over multiple hops. Note that if the data length is set to a number of bytes
that is longer than the number of bytes that can be transmitted by a base on a single hop, the
packet will be discarded. For the base, this value is set by the Set Base Slot Size command. A
packet will not be transmitted until the entire packet has been sent to the radio, regardless of
the amount of time it takes.
If the remote hosts can determine what data is directed to them in point-to-multipoint mode,
the data can be sent to the base station without using a packet format. In this situation,
broadcast mode is selected at the base station by using the Set Default Handle and selecting
mode. That is, raw unformatted data is sent from the host to the radio and is received as raw
data at the receiving end. The addressing and error detection and correction are still
performed by the radios, but it is transparent to the user application. To set up a point-to-
point network, one radio has to be set up as a base station. When the radios are powered on,
the base station will send out the synchronization signal at the beginning of each hop. The
remote will synchronize with the base and automatically request registration. Once the
remote is registered, the radios can transmit data. Protocol mode operation is available in
point-to-point mode if desired.
If the base station is to be responsible for directing data to a specific remote in point-to-
multipoint mode, the data sent to the base station by the user application must adhere to a
packet format. This allows transmissions from the base station to be directed to a specific
remote. Data received by a base station from a remote is similarly formatted to identify to
the user application the remote that sent the transmission. The remotes may still use
transparent mode without formatting to send data to the base, if desired. The WIT5811
protocol format is described in detail below. The protocol format is selected through the Set
Protocol Mode command.
Base radios can use protocol modes to insure that a packet is transmitted to the base without
being broken up over multiple hops. Note that if the data length is set to a number of bytes
that is longer than the number of bytes that can be transmitted by a base on a single hop, the
packet will be discarded. For the base, this value is set by the Set Base Slot Size command. A
packet will not be transmitted until the entire packet has been sent to the radio, regardless of
the amount of time it takes.
If the remote hosts can determine what data is directed to them in point-to-multipoint mode,
the data can be sent to the base station without using a packet format. In this situation,
broadcast mode is selected at the base station by using the Set Default Handle and selecting
3FH
as the default handle. In this mode, the automatic retransmission of unsuccessful
transmissions is disabled. This is required since all of the remote modems will attempt to
acknowledge each base transmission when ARQ is enabled. Transmissions that are received
with errors are discarded by the radio. The remote devices must be able to detect a missing
packet and request a retransmission by the base device.
acknowledge each base transmission when ARQ is enabled. Transmissions that are received
with errors are discarded by the radio. The remote devices must be able to detect a missing
packet and request a retransmission by the base device.