| Abbreviation | Definition |
|---|---|
| ROM | Read-Only Memory |
| RPC | Remote Procedure Call |
| RRDC | Road Racing Drivers Club |
| RS-423A | EIA standard for transmitting serial data |
| RSDP | Root System Description Pointer |
| RSS | Receive-Side Scaling |
| RSSI | Received Signal Strength Indication |
| RST | ReSeT |
| RT | Real Time |
| RTC | Real-Time Clock |
| RTCP | Real Time Control Protocol |
| RTP | Real-time Transport Protocol |
| RW | Readable/Writable |
| S/PDIF | Sony/Philips Digital Interface Format |
| S/T | Pseudo-Ternary |
| SAL | System Abstraction Layer |
| SAM | SCSI (Small Computer System Interface) Architecture Mode |
| SAP | Secondary Audio Programming |
| SAPIC | Streamlined Advanced Programmable Interrupt Controller |
| SAS | Serial Attached SCSI (Small Computer System Interface) |