These are terms used to describe what frequency a particular carrier uses to broadcast their signal.

• iDEN: 806-824 and 851-869
• Cellular: 824-849, 869-894, 896-901, 935-940
• PCS: 1850-1910 and 1930-1990

Dual and Tri Band mean the phone or amplifier is compatible with multiple bands, Dual meaning PCS and Cellular. A Dual Band amplifier will be compatible with the vast majority of US Carriers in most areas.