设计了一种带有RS - 485接口的交流变频控制器，它硬件接口简单，通讯可靠性高。
A variable frequency inverter with a RS-485bus communication interface is designed. It has the advantages of simple hardware interface and high reliability of communication.
但是如果没有它，蓝牙硬件可能只会在传递进的远程蓝牙设备中搜索第一个设备上的服务，而忽略其他设备。
Without it though, your Bluetooth hardware may only search for services on the first remote Bluetooth devices that you pass in, and it may ignore the others.
在它上面没有硬件的供应；只需把应用程序部署到其中—部署是免费的。
There is no provisioning of hardware on it; you simply deploy your application to it - you can do this for free.
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