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串行端口的引脚定义

硬件: Serial>>RS-232>>PCI-8432/2

问题: 串口的引脚定义是怎样的? 用于loop back测试时需要连接哪些引脚?

解答: RS-232是单端串行协议而RS-485 和 RS-422 是 差分的串行协议. RS-232, RS-422 和 RS-485 的引脚图如下.

loopback 测试是将信号从通信设备发出然后自己接收，用于测试设备是否工作正常 . 下图分别从RS-232 和 RS-422/RS-485三种情况给出了自发自收测试时哪些引脚需要连接.
RS-232

RS-422 和 RS-485

相关链接: Developer Zone: Serial Loop Back Test for LabVIEW
KnowledgeBase 2WR9LNHW: How Do I Do a Loop Back Test with a 485 Port in Two Wire Mode?

附件:


- Serial ports.bmp
- RS-232 loopback.bmp - RS-485 and 422 Loopback.bmp


报告日期: 04/24/2007
最近更新: 01/05/2008
文档编号: 48NB9TBH

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