Many phones are advertised as being "tri-mode" or "quad-band", etc. These refer to the combination of technologies and frequency bands the phone supports.

Examples of modes include "CDMA 1900", "WCDMA 1700", and "LTE 700". There are many other combinations. The first part is the technology, while the number represents the frequency band.

LTE and WCDMA are two major current technologies.

The 700, 750, 800, 850, 1700, and 1900 bands are used in the US. The 900, 1800, and 2100 bands are for use overseas.