O-Groups

The groups designated with "O" and a second letter like OA etc. are groups of electronic materiel and associated equipment.

OA Miscellaneous groups (Groups not otherwise listed)

OB Multiplexer and/or demultiplexer groups

OD Indicator groups

OE Antenna groups

OF Adapter groups

OG Amplifier groups

OH Simulator groups

OI Cryptographic groups

OJ Consoles and console groups

OK Control Groups

OL Data Analysis and Processing Groups

OM Modulator and/or demodulator groups

ON Interconnecting Groups

[[OP Power Supply groups (All non-rotating types)

OQ Test Set groups (All types OR Receiver groups)

OS Satellite groups

OT Transmitter groups

OU Converter groups

OV Generator groups (All types including power generating equipment)

OW Terminal groups Telegraph, radio, telephone, etc.

OX Coder, recoder, interrogator, transponder groups

OY Radar Set groups (not used if more specific indicator applies)

OZ Radio Set groups (not used if a more specific indicator (OE, OR, OT) applies)