What is Dual-band / Tri-band / Quad-band?

Dual-band also known as dualband refers to functionality that enables a cellphone to operate at both the 1800 MHz and 900 MHz spectrum. Dualband works in Africa, Asia, Europe, and South America.

Tri band phones also know as triband are cell phones that operate on three frequency bands: 900 MHz, 1800 MHz and 1900 MHz. Consumers can use triband phones in Africa, Asia, Europe, nearly all of North America, New Zealand and Australia.

Quad band literally means four bands and describes a mobile phone supporting four frequency bands. Quadband covers the 850 Mhz, 900 MHz, 1800 MHz and 1900 MHz frequency ranges. A quad-band cell phone enables roaming almost anywhere globally.