# Communications

- [NPN output](/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/communication/oct-output-setup.md)
- [Analog current output (4-20mA)](/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/communication/current-output.md)
- [RS485 and Modbus RTU Setting](/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/communication/rs485-setup.md)
- [Modbus RTU Protocol](/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol.md)
- [Read-Only Memory (ROM)](/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/read-only-memory-rom.md)
- [Read-Only Memory (ROM) – List](/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/read-only-memory-rom/read-only-memory-rom-list.md)
- [Read-Only Memory – Read Command (04)](/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/read-only-memory-rom/read-only-memory-read-instruction-04-and-memory-lists.md)
- [Single Bit Data Read/Write Commands (01/05) (Commonly Used in HMIs)](/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/single-bit-data-read-write-commands-01-05-commonly-used-in-hmis.md)