| SNDCP | Subnetwork Dependent Convergence Protocol | 子网相关会聚协议 |
| SNICP | Subnetwork Independent Convergence Protocol | 子网无关会聚协议 |
| SNPA | Subnetwork Point of Attachment | 子网连接点 |
| SNSDU | Subnetwork Service Data Units | 子网服务数据单元 |
| SA | Subscriber Application | 用户应用 |
| SIM | Subscriber Identity Module | 用户对等模块 |
| SIMI | Subscriber Identity Module Interface | 用户对等模块接口 |
| SPN | Subscriber Premises Network | 用户基地网 |
| SU | Subscriber Unit | 用户单元 |
| SS | Supplementary Services | 补充业务 |
| SCR | Sustainable Cell Rate | 可维持信元速率 |
| SCR | Sustained cell rate | 能支持的信元速率 |
| SMDS | Switched Multimegabit Data Service | 交换式多兆位数据服务 |
| SVCC | Switched Virtual Channel Connection | 交换虚信道连接 |
| SVC | Switched Virtual Circuit | 交换虚电路 |
| SE | Switching Element | 交换要素 |
| SER | Symbol Error Rate | 符号差错率 |
| SCF | Synchronization and Convergence Function | 同步与会聚功能 |
| SDLC | Synchronous Data Link Control | 同步链路控制 |
| SDH | Synchronous Digital Hierarchy | 同步数字系列 |
| SFET | Synchronous Frequency Encoding Technique | 同步频率编码技术 |
| SYN | Synchronous Idle Character | 同步空闲字符 |
