There may be a variety of reasons why a phone terminal does not support 4G or 5G networks. Here are some possible causes and solutions:
Hardware limitations: Some older or low-end phones may not have the hardware to support 4G or 5G networks. This is usually due to the phone's baseband chip or RF chip not supporting higher network frequency bands. In this case, upgrading the phone to a new model that supports 4G or 5G May be the only solution. Network coverage issues: In some areas, 4G or 5G networks may not yet have full coverage. This can result in phones not being able to connect to these networks even if they support them. You can try using your phone in a different location or network environment to see if you can connect to a 4G or 5G network. Carrier support: Make sure your phone is supported by a carrier that offers 4G or 5G service in your area. Some phones may only support certain carriers or network bands. You can contact your carrier to find out if they support your phone model and network band. Software Update: Some phones may require a software update to enable 4G or 5G support. Make sure your phone's system and network Settings are updated to the latest version. You can check and install updates through your phone's Settings menu or the official software update tool.
Network configuration issues: Sometimes, the phone's network configuration may be incorrect, resulting in an inability to connect to 4G or 5G networks. You can try resetting your phone's network Settings and then reconfiguring the network connection. The exact steps may vary depending on the phone model, and you can find the relevant options in your phone's Settings menu. In short, not supporting 4G or 5G networks may involve multiple aspects such as hardware, network coverage, carrier support, software updates, and network configuration. By examining and trying the above solutions, you may find a way to solve the problem. If the problem persists, you may want to consider upgrading your phone or contacting your phone manufacturer or carrier for further support.