J-carrier - Computer Definition
A hierarchy of standards for digital transmission that essentially is the Japanese version of the United States T-carrier digital carrier system.At levels one and two, J-carrier mimics T-carrier with respect to the signaling rates, but diverges at level three and beyond. J-carrier also uses a different PCM companding technique (A-law rather than µ-law). As J-carrier is medium-independent, it can be provisioned over any of the transmission media, at least at the J-1 rate of 1.544 Mbps. (At the J-3 rate of 32.064 Mbps, twisted pair is unsuitable due to issues of signal attenuation.) The fundamental building block of J-carrier is a 64-kbps channel, referred to as DS-0 (Digital Signal level Zero).Through time division multiplexing (TDM), J-carrier interleaves DS-0 channels at various signaling rates to create the services that comprise the Japanese digital hierarchy, as detailed in Table J-1. Table J-1: Japanese Digital Hierarchy: J-carrier
|J-carrier Level||Data Rate||64-kbps Channels (DS-0s)||Equivalent J1s|
|0||64 kbps||1||Not applicable|
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