Digital telephone switching network
digital telephone switching service
automatic digital switching
Digital Switching
数字切换器
数字合成
数字交换
时间区分数字式交换
空间区分数字式交换
digital switching device
digital switching devices
digital switching modular architecture
Digital Switching Network
Digital switching noise
digital switching system
Digital Telephone Exchange
Digital Telephone Exchange TXD
Digital Telephone Network
Digital Telephone Network DTN
local digital switching
radio digital telephone
space-division digital switching