> 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 enables the best possible voice quality currently available for landline or VoIP calls and is automatically included in 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. No additional bandwidth from your internet connection is required.

#### **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 call 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 device.

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

A phone call naturally always goes in two directions. If the person on the other end of the line does not have HD telephony, you will automatically call in normal voice quality. But: Many telephony and device providers have already switched to HD or are working on it. It can therefore be assumed that HD telephony will be the absolute standard in the near future – and with sipgate, you are already perfectly set up for it now.


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