To receive the audible alerts from the GHP 10 the autopilot buzzer is wired to the course compass unit(CCU). 010-11056-00 Features: Autopilot Buzzer, Works with Garmin Models: GHP: 10, 10V, 12, 20 for Steer-by-wire, 20 for Hydaulic Steering Corepack, 20 for Viking, 20 for Yamaha helm Master, 20 w/ SmartPump, GHP Compact Reactor, GHP Reactor: Hydraulic Autopilot, w/ SmartPump, for Viking VIPER, for Volvo-Penta, for Yamaha Helm Master"