有关ISDN的基本概念

　　ISDN is constructed to an integrated service digital network on the present foundation of local telephone networks： WAIMAOZU.COM

　　ISDN is able to provide subscriber with voice、data、picture、fax and each type integrated services.Morever， it could realize？"one unit connects more，three units occupies one line" one pair of telephone lines can connect to more different type terminals （max 8），each terminals can be communicated simultaneously （max 3），terminal types include：ISDN router，terminal adapter，，ISDN video telephone， digital telephone，G4 fax；other special terminal equipments are with ISDN interfaces. ~0 X)

　　Basic Rate： Total is 2B+128Kbps wideband ，RJ45 interface.

　　Primary Rate：30B+D channel， 2Mbps Wideband，RJ45 or BNC interface.

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　　B channel： Basic channel，64Kbps；D channel： control channel，16Kbps.

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