With ISDN service, signaling that must be conveyed between the user station and the local switch is carried on a separate digital channel called the D channel.
与必须表达在用户驻地和本地开关之间的ISDN服务，发信号继续称D渠道的一条分开的数字通道。
With ISDN service, signaling that must be conveyed between the user station and the local switch is carried on a separate digital channel called the D channel.
与必须表达在用户驻地和本地开关之间的ISDN服务，发信号继续称D渠道的一条分开的数字通道。
应用推荐