资 源 简 介
使用更新的有线接口稳定关键工业物联网连接
物联网产业（IIoT）意味着有更多的传感器，传感器和执行器，需要连接。虽然无线链路似乎是简单的连接解决方案，他们受到安全问题，较高的初始成本，以及在工业环境中的RF传播的不确定性。
相反，许多应用程序都使用传统的但更好的服务更好的基于RS-232、RS-422和RS-485协议，RS - 423收发器。这些可以帮助设计人员优化系统的可靠性，信号完整性和成本效益。通过这些有线链路收集的汇总数据，然后可以通过一个强大的有线或无线连接到后端网络和互联网连接。
然而，有一些新的要求被放在这些既定的和成功的有线标准，超越他们原来的要求。更高的信道计数和密度，以及更快的数据速率，是具有挑战性的设计师制定满意的解决方案，网格与新的任务，涵盖ESD（静电放电），低电压操作和容错要求。
What is RS-232 and its related standards？
Recommended Standard 232 （RS-232） was released by the Electronic Industries AssociaTIon （EIA） in 1962. Its original role was to connect computers to electromechanical teletypewriters （often called “Telex” machines）， modems， and printers， but the standard was soon adopted for many other interface applicaTIons.
RS-232 is a relaTIvely simple standard and is limited to point-to-point serial links with a single sender and receiver. It can be used for simplex， half-duplex， and full-duplex links， and was limited to 19，200 baud （not necessarily the same as bits/sec， but often is）。 The most widely used revision， RS-232D， specified use of ±25 volts for the signaling of ones and zeros. Note that the standard did not specify the encoding of the data itself. It only called out the signal levels， slew rates， start/stop framing， and basic handshaking for the connecTIon.
To meet the need of growing networks， the standard was extended to RS-422， RS-423， and finally RS-485， which added multi-drop capability， higher speeds， and longer distances （Table 1）.
