MarkV audible alarms

See the 'Speedtronic(tm) Mark V Maintenance Manual', GEH-5980, Sect. 2.6, "Alert Box Function." Note that this option was not available early in the production of Mk V turbine control panels, and only works with <I>s running IDP ver. 3.5 or greater. It may also require a serial port expander board, usually referred to as a "Digiboard" (name of the manufacturer).

Since it was not available with early production Mk Vs, it's probably not documented in every version of the Maint. Manual....

It's probably no longer available as an option from GE, either.