> 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/wie-funktioniert-die-hd-telefonie.md).

# How does HD telephony work?

HD telephony in sipgate: highest voice quality for VoIP calls – automatically included in all plans.

HD telephony enables the best possible voice quality currently available for landline or VoIP calls and is automatically included with all sipgate plans.

#### **What does HD telephony sound like?**

The simple answer: clearer, fuller, and more natural. The technical background: Unlike conventional telephony, a wider frequency spectrum of the voice is transmitted. This does not require any additional bandwidth from your internet connection.

#### **What do you need for HD telephony?**

You do not need to make or adjust any settings in your sipgate account. If your hardware meets the requirements, you will automatically make calls in HD. For this, you need HD-capable phones or end devices. In detail, this means that your VoIP phone must support the required [Codec](https://help.sipgate.de/hc/de/articles/4415497075729) (G722 and Opus), which can transmit speech in HD quality. Many phones already support exactly these codecs, but you may need to adjust the configuration of the end device.

#### **You meet all the requirements, but don't hear any difference?**

A phone call always goes both ways, of course. If the person on the other end of the line does not have HD telephony, the call will automatically be in standard voice quality. But many telephony and device providers have already switched to HD or are working on it. So it can be assumed that HD telephony will soon become the absolute standard—and with sipgate, you're already perfectly set up for that now.


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