AARP
AppleTalk Address Resolution Protocol
ARP
Address Resolution Protocol (Internet)
ARP
Active Rollover Protection
ARPA
Advanced Research Projects Agency, USA
ARPA
Automatic Radar Plotting Aid
AMTOR
Amateur Microcomputer Teleprinting Over Radio
ANARC
Association of North American Radio Clubs
ARDF
Amateur Radio Direction Finding
ARI
Autofahrer Radio Information
ARRL
American Radio Relay League