Acknowledged communications: Acknowledged mode
9XTend-PKG-R RS-232/485 RF Modem User Guide
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Polling mode theory of operation
A Polling Base device cycles through a sequential range of addresses. The Polling Base polls each Polling Remote
device, waits for a response, then poll the next remote address in the sequence. Each Polling Remote responds by
sending the data from its DIN buffer following the RB and RO parameters. When there is no eligible data to send, the
Polling Remote does not respond. The Polling Base polls the next address in the polling sequence after a short delay.
Configure a Polling Base
To configure a device as a Polling Base:
1. Set MD = 3.
2. Set MY = 0.
3. Set the sequential range of polling addresses using PB and PE.
4. (Optional) Enable Basic Reliable Delivery (MT
≥
0). The firmware also supports Acknowledged Reliable Delivery.
For more information, see
5. (Optional) Use PD to configure a delay between polls to slow down the system, if needed.
6. (Optional) Enable API Mode to address remote devices within polling range on a packet-by-packet basis.
Configure a Polling Remote
To configure a device as a Polling Remote:
1. Set MD = 4.
2. Configure sequential source addresses for all remote devices using MY.
3. Set DT to point to the Polling Base (DT = 0x0000).
4. (Optional) Enable Basic Reliable Delivery (MT >= 0). The firmware also supports Acknowledged Reliable Delivery.
For more information, see
Acknowledged communications: Acknowledged mode
Use Acknowledged mode for applications that need reliable delivery. If messages are smaller than 256 bytes, use the
RB and RO commands to align RF packets to application packets.
Characteristics
Reliable delivery through positive acknowledgments for each
packet.
Throughput, latency and jitter vary depending on the quality of the
channel and the strength of the signal.
Required parameter
values (TX device)
RR (Retries) >= 1
Related commands
Networking (DT, MK, RR), Serial Interfacing (PK, RN, RO, RB, TT)