Solid State refers to the storage of data in semiconductor memories or integrated circuits. Older technology usually referred to as "tape" technology utilized electromechanical methods of data storage.

Solid State memory does not require scheduled maintenance or overhaul. Therefore, there are potential cost savings to operators and owners. Also data is easier to retrieve and is readily available to for monitoring the performance of the aircraft.

By definition, Frequency-Shift Keying or FSK is a form of frequency modulation in which the modulating signal shifts the output frequency between predetermined values. In relation to aircraft recorders, it is simply a data format that is utilized to input GMT (Greenwich Mean Time). Some recorders are able to either handle GMT via low speed ARINC 429 input or FSK or both.

The Underwater Locator Beacon (ULB) is usually the only part that requires any type of periodic maintenance for most Cockpit Voice Recorders (CVR) and Flight Data Recorders (FDR). This maintenance includes cleaning and testing the ULB every 2 years and replacing the battery every 6 years. It should be noted that some aircraft maintenance programs may include testing and/or bench testing of CVRs or FDRs as part of the aircraft maintenance program.