Although the FRITZ!Box is not CAT-iq certified, it supports many of the services and functions defined in CAT-iq. For example, the FRITZ! function 'HD telephony' complies with the new standard and is therefore fully compatible with all CAT-iq-based products for HD telephony available on the market. CAT-iq 2.0-compatible cordless phones from other manufacturers can also use convenience functions such as toggling calls, 3-party conference calls, CLIP/CNIP, and accessing the FRITZ!Box phone book and call list.

The FRITZ!Box also supports CAT-iq SUOTA (Software Update Over The Air), which allows cordless phones from other manufacturers to update their software via the FRITZ!Box.

In addition, the FRITZ!Box and FRITZ!Fon models offer a multitude of other functions that cannot currently be implemented with the CAT-iq standard. For this reason, we do not currently consider it necessary to seek certification, nor are we planning to do so.