> For the complete documentation index, see [llms.txt](https://help.sipgate.de/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.sipgate.de/cloud-telefonanlage/en/using-sipgate/telefonie/was-ist-das-besetztlampenfeld-blf.md).

# What is the busy lamp field (BLF)?

When you want to display the **phone status** of colleagues on your own phone, the busy lamp field (BLF) is the feature of your choice. It is included in the business L and XL plans. To use the function, the users created must have an **internal extension** assigned. Once correctly configured on the device, the BLF shows these three statuses:

* **available**: colleagues are not in a call, the busy lamp is off.
* **is busy**: colleagues are speaking, the busy lamp lights up continuously.
* **ringing**: colleagues are being called right now, the busy lamp flashes.

The BLF configurations differ from model to model.

You can find the instructions for this on the manufacturers' websites and in the documentation supplied with your phone.

We have tested the BLF configuration on a whole range of phone models; here you will find the [configuration guide for Snom,](https://help.sipgate.de/hc/de/articles/4408426635921) the [configuration guide for Gigaset](https://help.sipgate.de/hc/de/articles/4408434099217), which [configuration guide for Yealink,](https://help.sipgate.de/hc/de/articles/4408427192081-BLF-Konfiguration-f%C3%BCr-Yealink) the [configuration guide for Tiptel](https://help.sipgate.de/hc/de/articles/4408427390481-BLF-Konfiguration-f%C3%BCr-Tiptel), which [configuration guide for Grandstream.](https://help.sipgate.de/hc/de/articles/4408427518097-BLF-Konfiguration-f%C3%BCr-Grandstream)

In your sipgate account, as an alternative to BLF, under **My Telephony** the [**presence display**](https://help.sipgate.de/hc/de/articles/4408234555025).\
This shows you which users are currently available.

If a user is in a call, the corresponding tile with the internal extension is shown in red.

{% hint style="warning" %}
**Important:** All users must be assigned a **internal extension** be assigned.
{% endhint %}


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