Learjet audio question
 

Dear Lear Experts,

Can anybody tell me how the variuous audio warnings are generated on the LJ-60? ( T/O Config, Cabin Alt, Gear, A/P, Y/D Disconnect, NW Steering Disconnect) By a tone generator? Individual horns? Are the cockpit speakers and headphones used for this purpose? On the top of the copilot's C/B panel there are three small horns. What are their exact function?
No trace in the 60 manuals. Maintenace manual perhaps?
Many thanks.