定义：ISDN(综合服务数字网络)，是一个国际转换标准，是为了语音和数据的数码拨号上网电话服务。

Definition of: ISDN (Integrated Services digital Network) an international standard for switched, digital dial-up telephone service for voice and data.

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定义：ISDN(综合服务数字网络)，是一个国际转换标准，是为了语音和数据的数码拨号上网电话服务。

Definition of: ISDN (Integrated Services digital Network) an international standard for switched, digital dial-up telephone service for voice and data.

youdao