比较 RS-232 与RS-449 的电气特性。 -题库考试答案搜索网

比较 RS-232 与RS-449 的电气特性。

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2022-02-21 20:49

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正确答案

RS-232规定逻辑“1”的电平为：-15~-5，逻辑“0”的电平为+5~+15。两设备的最大距离也仅为15米，而且由于电平较高，通信速率反而影响。接口通信速率小于等于20Kbps。RS-422由于采用完全独立的双线平衡传输，抗串扰能力大大增强。又由于信号电平定义为正负6伏，当传输距离为10m时，速率可达10Mbps；当传输距离为1000m时，速率可达100Kbps。
RS-423，电气标准是非平衡标准。它采用单端发送器和差动接收器。当传输距离为10m时，速率可达100Kbps；当传输距离为1000m时，速率可达10Kbps。

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