The Narco AT-50 is a very common transponder, and the original "50" series model. The AT-50 offers basic transponder functionality at a reduced cost (compared to King and Collins). The AT-50 features:
- 4096 discrete codes
- Mode C compatibility
You may also be interested in an Encoder to use with this AT-50. When installed with an Encoder, the AT-50 will report both your position and altitude to ATC (Mode C).