| Abbreviation | Definition |
|---|---|
| RTS | Request To Send |
| RTT | Roof Top Tower |
| RTTE | Radio and Telecommunications Terminal Equipment |
| RTU | Remote Terminal Unit |
| RTU | Remote Test Unit |
| RTX | Real Telephone eXchange |
| RTZ | Rate for Transmission service for a Zone load |
| RUIM | Removable User Identification Module |
| RWF | Roaming Wireless Framework |
| RWI | Real Wireless Intelligence |
| RWL | RF (Radio Frequency) / Wireless Laboratory |
| RWT | Receiver Wait Time |
| Rx | Receiver |
| RXJ | Receive-Protocol Reject |
| RYC | Returned Your Call |
| RYP | Romanian Yellow Pages |
| RYP | Russian Yellow Pages |
| RZ | Receive ZModem |
| RZ | Return to Zero |
| S | Subscriber |