The FCC has created ISM frequencies. That’s Industrial-Scientific-Medical. Vendors can sell equipment that operates on those bands without licensing. There are a lot of these items:
- microwave ovens
- garage door openers
- WiFi Routers
- Bluetooth
- TV
- and so on
An older WiFi phone may operate on 900mhz which cuts through walls/floors better. 2.4Ghz is better than the newer 5ghz WiFi in that too but that can carry more data for streaming and such.
When there are adjacent signals, devices will step down their data rate. In some cases that step down has a data rate that loses some of the signal. In data, the checksum requires the data be re-transmitted. In a real-time devices such as attaching to your phone, the signal remains lost – hence the cutting out.