整合服务数位网路在数位线路上被使用就如同在声音等级的线路上。

ISDN is used on digital lines as well as on voice-grade lines.

youdao

整合服务数位网路在数位线路上被使用就如同在声音等级的线路上。

ISDN is used on digital lines as well as on voice-grade lines.

youdao