光纤同轴混合网    Hybrid Fiber and Coax Network HFC

混合光纤同轴网    Hybrid Fiber/coax HFC

混合集成电路    Hybrid Integrated Circuit HIC

液压压线钳    Hydraulic Pressure Crimper

液压冲击钻    Hydraulic Pressure Percussion Drill

温湿度计    Hygrothermograph

超帧    Hyperframe

假设参考电路    Hypothetical Reference Circuit HRC

假设参考通道    Hypothetical Reference Path HRP

假定信令参考连接    Hypothetical Signaling Reference Connection HSRC

滞后现象    Hysteresis

PD    H物理接口 PDH Physical Interface PPI

SD    H管理网络 SDH Management Network SMN

SD    H设备时钟 SDH equipment clock SEC