Question: what are the differences between dual-band tri-band and quad-band phones?
Answer: Dual-band - also known as dual-band or dualband. A dual-band phone operates at both the 900 MHz and 1800 MHz spectrum. ... 
Dual band phones are also used to enable roaming between different countries. ... 
Tri-band - also known as tri-band or triband. ... 
Quad-band -also known as quad-band or quadband.