全球通信 global communications
灵活性 flexibility
端到端的数字连接 end-to-end digital connectivity
开放网络 open network
语声编码 voice encoding
综合业务数字网 integrated services digital network
系统结构 infrastructure
国际标准化组织International Organization for Standardization
通信载体 communication carriers
传输媒体 transmission medium
接口设备 interface equipment
带宽限制 band limitation
交换设备 switching equipment
语音编码 voice encoding
脉码调制 pulse code modulation
基本接入 basic access
综合业务数字网 the integrated services digital network
国际标准化组织 the International Organization for Standardization
由于传输媒体导致的质量下降 degradation due to the transmission medium
4kHz话路中所固有的带宽限制 band limitations inherent in a 4kHz voice channel
标准化的接口 standardized ports
脉（冲编）码调制 pulse code modulation
数字通信 digital communication
ISDN的标准和系统结构 ISDN standards and system architecture
全球通信 global communication
数字技术的逐步应用 progressive application of digital technology
共同通信载体 public communication carriers
高质量 enhanced quality
大量的接口设备 substantial quantity of interface equipment
带宽的限制 band limitations
端到端的数字连接 end-to-end digital connectivity
语音编码技术 voice encoding techniques
基本接入信令速率 basic access signaling rate
统一的接入 universal access