User's Manual

Protocol Operation
Crescendo VHF Half-Duplex User Manual Page 42 of 74
For the example in Figure 12 the following mapping would occur:
1. A protocol packet with an address of 1 would be sent to radio address 1001.
2. A protocol packet with an address of 4 would be sent to radio address 1004.
3. A protocol packet with an address of 9 would be sent to radio address 1009.
4. A protocol packet with an address of 10 would be sent to radio address 1010.
5. A protocol packet with an address of 11 would be sent to radio address 1011.
6. A protocol packet with an address of 15 would be sent to radio address 1011.
7. A protocol packet with an address of 2 would be sent to radio address 2. Note the unused entry (1).
8. Any protocol packet with an address that does not have a matching entry will be sent to a radio
address that matches the protocol address.
Note that only DNP and Modbus RTU protocol utilise the protocol mapping table and that the mapping is
only applied to packets arriving over the serial port.
6.11 Multiple Protocol Modes
The Crescendo is a dual serial port radio modem, and both ports can be independently configured with
different protocol modes. Using both ports for data may result in increased latency, owing to greater
bandwidth requirements and increased probability of collision.