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# Which Airwallet unit do you have?

Our installation guides show the wiring for two kinds of Airwallet PRO unit, and many machines can also be installed with a plug-in harness. Check which one you have before you start.

### Check your unit

Read the model number on the label on the back of the unit, or count the wires in its cable.

| Unit | Cable | In the installation guides |
| --- | --- | --- |
| PRO310–PRO330 | 7 wires | Use the **PRO310–330** column |
| PRO340 | 8 wires | Use the **PRO340** column |
| PRO400 with Universal Harness | 8 wires | Use the **PRO340** column |
| PRO400 with a machine harness | Harness plug | Use the PRO400 harness guide for your machine |

Wires 1–7 do the same job on the PRO310–330 and the PRO340. Wire 8 on the PRO340 is a 24V output, and most installations do not use it.

### If the guide tells you to move a wire inside the unit

Some machines report that they are busy with a 24V signal (DC busy). On a PRO310–330 you move wire no. 5 from port 10 to port 7 inside the Airwallet unit. On a PRO340 you do not move anything: use wire no. 8 instead.

ASKO machines also need wire no. 7 moved from the NC terminal to the GND terminal inside the unit. This applies to every Airwallet unit.

### Harness installations

- PRO400 units connect with a machine-specific harness. Find yours in the [Airwallet PRO400 Harness Model Identification Guide](https://wiser.airwallet.net/en/article/harness-model-identification-guide-1jq7a03/).
- A PRO400 with the Universal Harness does the same job as a PRO340, and the two can replace each other. Wire it like a PRO340.

### Unit guides

- [Airwallet PRO310 to PRO330 - Installation guide](https://wiser.airwallet.net/en/article/airwallet-pro310-to-pro330-installation-guide-1qngm4d/)
- [Airwallet PRO340 - Installation guide](https://wiser.airwallet.net/en/article/airwallet-pro340-installation-guide-vfbp9l/)
- [Airwallet PRO400 - installation guide](https://wiser.airwallet.net/en/article/airwallet-pro400-installation-guide-1g4tfz5/)