---
title: "Contact closure input"
canonical: "https://docs.cuesystem.com/space/PRODUCTS/1046708272/Contact%20closure%20input"
format: markdown
---
This port is typically used to connect potential-free contacts such as switches, buttons or optocouplers.  The port provides digital input for reading the contact status.

**Connector pinout**

|  |  |  |
| --- | --- | --- |
| 2-pin terminal block | Terminal | Description |
| ![image-20240403-112811.png](media://8e1c528d-25f1-4d76-bf05-6b8e4583beb8) | CC- | Contact closure input - |
| CC+ | Contact closure input + |

**Parameters**

- Digital input
- 2-pin spring clamp terminal block, max. wire cross-section 0,5 mm<sup>2</sup>
- For potential-free galvanically isolated contact only
- Input ESD protected
- Digital levels 0: < 0.6 V, 1: > 2.5 V
- Internal pull-up resistor to 3,3V

> ⚠️ The input is designed for **potential-free contacts only**. Since the input is connected to internal circuits, the **contacts must be galvanically isolated** from the other external circuits.


**Examples of use:**

| **Connection** | **Usage** |
| --- | --- |
| ![image-20240403-150433.png](media://ca895a62-9ce3-4133-83a9-9fcf365a709a) | Detecting a pushbutton or switch. |
| ![image-20240403-161527.png](media://55d18ac6-5725-4dc2-bffd-0fd3619ea765) | Optocoupler status detection. |