Simrad GC80 - 6.1 General; 6.2 Using the Extension menu

Simrad GC80/85 Double System Controller
76
988-12721-001
Category A
Alarm that can only be acknowledged (ACK button) by operating the
system.
Category B
Alarm that can be acknowledged (ACK button) by operating either the
system or external equipment (CAM-HMI).