| 单词 | PBX (Private Branch eXchange) |
| 释义 | PBX (Private Branch eXchange) A voice-optimized switching system physically located on the cus- tomer premises, serving the internal station-to-station communications requirements of one or more user organizations and with trunk circuits connecting to the public switched telephone network (PSTN) via one or more central office (CO) switches, and perhaps one or more other PBXs composing a private network.The term refers to the fact that the PBX originated as a switching system located on the subscriber’s private premises and serving the subscriber’s private communications requirements, while functioning as a branch (i.e., partition) of the public exchange . The first PBX was placed into service in the Old Soldiers’ Home in Dayton, Ohio, in 1879. The first systems were non-standard modifications of CO switches. AT&T offered the first standard PBX, the No. 1 PBX, in 1902.The evolution of PBX technology can be organized along generational lines, as shown in Table P-1. |
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