Choose a protocol adapter

Pick the right communication adapter (Modbus, ASCII/SCPI, MQTT, BLE, HTTP) for your simulated device and your SUT.

SPX models can expose signals over protocol adapters so your Software Under Test (SUT) can talk to a simulation as if it were real hardware.

Use this page to pick the adapter that matches your client/driver, then follow either:

• the adapter reference docs under Communication Adapters, or

• a runnable baseline from spx-examples (models + tests).

Quick routing

Adapter	When to use	Docs	Example model (spx-examples)
Modbus TCP	PLC/HMI/device drivers using Modbus	Modbus	energy_meter_iem3000__modbus.yaml
ASCII / SCPI	Lab instruments, SCPI drivers	ASCII	multimeter__scpi.yaml
MQTT	IoT telemetry pipelines and brokers	MQTT	environment_sensor__mqtt.yaml
BLE	Mobile apps and BLE test rigs	BLE	temperature_sensor__ble_gatt.yaml
HTTP endpoint	Simple REST callbacks / webhooks	HTTP	air_quality_station__http.yaml

Note on ports (Docker)

Protocol adapters listen on TCP/UDP ports in the SPX Server container. If your SUT runs on the host, you must expose the adapter port(s) in your docker-compose.yml.

For a working baseline, spx-examples/docker-compose.yml already exposes common ports (API 8000, Modbus 502, SCPI/ASCII 5025, ...).

Next steps

• Example tutorial: Add Modbus TCP/IP to Your Simulation

• Deterministic QA flow: Use in Unit Tests (MiL)