What equipment do I need to use APRS?

A radio, a TNC capable of packet radio and software. Alternatively, you can use the radios from Kenwood: TH-D72, TH-D74, TH-D75, TM-D700, TM-D710 and the AT-D878UV from Anytone. An APRS tracker can also be used to transmit instead of a TNC.