R's

RAD - Rapid Application Development
RAD - Remote Antenna Driver
RADAR - Radio Detection And Ranging
RAD/RASP- Remote Antenna Driver / Remote Antenna Signal Processor
RADSL - Rate Adaptive Digital Subscriber Line
RAID- Redundant Array of Inexpensive Drives
RAM - Random Access Memory
RAM - Remote Access Modem
RARP- Reverse Address Resolution Protocol
RAS - Remote Access Server
RASP- Remote Antenna Signal Processor
RBB - Residential Broadband
RBOC- Regional Bell Operating Companies
RCF - Remote Call Forwarding
RDF - Radio Direction Finding
RDM - Report Display Manager
RDN - Relative Distinguished Name
RDP - Reliable Datagram Protocol
RECS- Reseller Electronic Communication System
REMOB - Remote Observation
REXEC - Remote Executable
REXX- Restructured Extended Executor
RF- Radio Frequency
RFC - Request For Comments
RFI - Radio Frequency Interface
RFI - Request For Information
RFNM- Request For Next Message
RFS - Remote File Service
RFS - Remote File System
RGB - Red-Green-Blue
RIP - Routing Information Protocol
RISC- Reduced Instruction Set Computing
RJE - Remote Job Entry
RLE - Run Length Encoding
RLL - Run Length Limited
RLOGIN- Remote Login
RM- Resource Management
RMA - Return Merchandise Authorization
RMS - Record Management Services
RO- Receive Only
ROM - Read Only Memory
RPC - Remote Procedure Call
RPG - Role Playing Game
RPM - Revolutions Per Minute
RSA - Rivest, Shamir and Adleman (Encryption)
RSEXEC- Resource Sharing Executive
RSH - Remote Shell
RSH - Restricted Shell
RSVP- Resource Reservation Protocol
RT- Real-Time
RTC - Real-Time Clock
RTCP- Real-Time Transport Control Protocol
RTF - Rich Text Format
RTFM- Read The F***ing Manual
RTL - Run-Time Library
RTP - Real-Time Transport Protocol
RTS - Request To Send
RTSP- Real-Time Streaming Protocol
RTTY- Radio Teletype
RU- Request Unit
RU- Response Unit
RVD - Remote Virtual Disk