# How the XS4 Face Device uses its camera, presence sensor and status light
> Find out what the XS4 Face Device camera and presence sensor capture, what the status light means, and what happens to your face images and biometric data.


The {{< glossary_term "xs4face_device" >}}XS4 Face Device{{< /glossary_term >}} is the reader next to the door.
It has three parts that you can see or that can see you:

- A camera
- A presence sensor
- A status light

This page explains what each part does and what happens to your face images.

## The camera {#camera}

The camera is a normal color camera.
It is on whenever the device is running.

The device keeps only the newest picture in its memory.
Each new picture replaces the one before it.
The device uses these pictures to:

- Spot movement in front of the door.
- Read special QR codes that installers show to the device.

The device sends a photo for face recognition only when both of these happen:

1. The presence sensor detects someone in front of the door.
1. The camera sees movement.

The device asks the camera for pictures of 1920 × 1080 pixels.
It sends each photo as a single JPEG image.

## The presence sensor {#presence-sensor}

The presence sensor is an infrared sensor.
It detects when someone is standing in front of the door.
It doesn't take pictures or record video.
It only tells the device that someone is there.

## The status light {#status-light}

The status light tells you what the device is doing.

| Light | What it means |
| --- | --- |
| Solid white | The device is ready. Step in front of the camera. |
| Flashing white | The device is checking your face. Stay still. |
| Green | Access granted. The door unlocks. |
| Red | Access denied. You don't have access to this door at this time. |
| Red, flashing 3 times | Something went wrong. Step away and try again. |

Other colors, such as yellow, blue or a sequence of colors, mean the device is being set up or serviced.
If you see one of these, contact your building manager.

## What happens to your face images {#face-images}

### On the device {#on-the-device}

The device doesn't save face images.
It holds the newest picture in memory only, and keeps replacing it with the next one.
When the device restarts, the picture in memory is gone.

The device doesn't compare faces itself.
It sends the photo to the {{< glossary_term "xs4face_server" >}}XS4 Face Server{{< /glossary_term >}} in your building.
The connection is encrypted, and the device and the server each prove who they are before the device sends anything.

### On the XS4 Face Server {#on-the-server}

The XS4 Face Server compares the photo with the people enrolled for your building.
It deletes the photo as soon as the comparison is done.

To recognize you, the server uses a face template.
A face template is a set of numbers made from the photo you gave when you enrolled.
The server doesn't keep your enrollment photo.
It makes the template and then deletes the photo.

The server keeps your face template until you remove your consent, or until your building's operator removes you from the system.

### In the cloud {#in-the-cloud}

The XS4 Face cloud keeps a record of each access attempt for 15 days.
These records don't include any face images.

The {{< glossary_term "xs4face_enrollment_service" >}}XS4 Face Enrollment Service{{< /glossary_term >}} holds the photo you uploaded when you enrolled.
The XS4 Face Enrollment Service keeps your photo until one of these happens:

- You delete your enrollment profile.
- You no longer have access to any buildings that use face recognition.

## Who controls your data {#who-controls-your-data}

The organization that manages your building decides to use XS4 Face.
It controls your personal data.
You will have been introduced to them and given access to their privacy policy when you enrolled and provided consent.
Salto provides the system and processes your data on that organization's behalf.

Salto controls the enrollment service and is responsible for your photo.
For details, see our [privacy policy](https://saltosystems.com/en/legal-data/privacy/privacy-policies/access-control-cloud-applications/).

For more information, see [data protection and your personal data](/xs4face/system-documents/software/data-protection) and your building operator's privacy policy.

## Your choices and rights {#your-rights}

Using your face to open doors is your choice.
You give consent when you enroll, and you can remove it at any time.
If you don't want to use face recognition, ask your building manager for another way to get in.

To remove your consent and delete your face template, see [disenrolling from the XS4 Face Enrollment Service](/xs4face/user-guide/user/disenrollment).
When you remove your consent for a building, the XS4 Face Server in that building deletes your face template.
To delete your enrollment photo as well, delete your enrollment profile.