Field Engineering Maintenance Manual
Provided by the ASK Keyboard Dictionary
A Field Engineering Maintenance Manual was a type of official document that could be available for a given computer, keypunch typewriter or terminal. FEMMs were prominent for IBM systems up to and including the 1980s. They were intended for technicians working externally to IBM and described how one could maintain such systems (including their keyboards and keyboard assemblies) whilst deployed, thus a useful source for information.