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RS‐232/485 RF Modem Product Manual – MAN0782‐02
Modes of Operation
Figure 3.3. Modes of Operation
Idle Mode
When not receiving or transmitting data, the modem is in Idle Mode. The modem uses the same
amount of power in Idle Mode as it does in Receive Mode.
The modem shifts into the other modes of operation under the following conditions:
The modem automatically transitions to Idle Mode after finished responding to these conditions.
Transmit Mode
When the first byte of serial data is received from the host in the DI buffer, the modem attempts
to shift to Transmit Mode and initiate an RF connection with other modems. After transmission is
finished, the modem returns to Idle Mode.
RF transmission begins after either of the following criteria is met:
1.
2.
Figure 3.4. Transmit Mode Data Flow
The character timeout trigger can
be disabled by setting RO to zero.
In this case, transmission will not
begin until RB bytes have been
received and are pending for RF
transmission. The RB parameter
may be set to any value between 1
and the RF packet size (PK),
inclusive. Note that transition to
Transmit Mode cannot take place
during RF reception; the RF
reception must complete before
the modem can transition into
Transmit Mode.
RS-232/485 RF Modems operate in five modes.
The RF modem can only be in one mode at a time.
•
Serial data is received in the DI Buffer (Transmit Mode)
•
Valid RF data is received through the antenna (Receive Mode)
•
Command Mode Sequence is issued (Command Mode)
•
Sleep Mode condition is met (Sleep Mode)
RB bytes have been received by the host and are pending for RF transmission.
[RB (Packetization Threshold) Command]
At least one character has been received by the host and is pending for RF transmission, and
RO character times of silence have been observed on the host.
[RO (Packetization Timeout) Command]
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