# Communication

- [OCT output](/qr/fp-as510-paddle-wheel-flowmeter-manual-en-v1/communication/oct-output.md)
- [4-20mA](/qr/fp-as510-paddle-wheel-flowmeter-manual-en-v1/communication/4-20ma.md)
- [RS485](/qr/fp-as510-paddle-wheel-flowmeter-manual-en-v1/communication/rs485.md)
- [Modbus RTU Protocol](/qr/fp-as510-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol.md)
- [Read-only memory read instruction(04) and memory lists](/qr/fp-as510-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/read-only-memory-read-instruction-04-and-memory-lists.md)
- [Read-write memory list](/qr/fp-as510-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/read-write-memory-list.md)
- [Read-write memory read instruction(03)](/qr/fp-as510-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/read-write-memory-read-instruction-03.md)
- [Read-write memory single Register write instruction(06)](/qr/fp-as510-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/read-write-memory-single-register-write-instruction-06.md)
- [Read-write memory double Register write instruction(30)](/qr/fp-as510-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/read-write-memory-double-register-write-instruction-30.md)