I often get questions about the Intel AMT serial port. Ever since the DTK started to make heavy use of it, serial-over-LAN has gotten a lot of attention. First, how do you change the COM port number of the Intel AMT serial port? The COM number (COM3: for example) is assigned by the operating system, so you don’t see that is any AMT/BIOS/MEBx option. You have to go into Microsoft Windows Device Manager, go to the properties of the “Intel(R) Active Management Technology – SOL” port. Then go into the “Port Settings” tab and press the advanced button. There, you can change the COM port.
Also, it’s often useful for application to be able to automatically detect the AMT serial port. In Intel AMT Outpost, I scan the device drivers looking for the “Intel(R) Active Management Technology – SOL” device and read the COM port number that follows in that string. Sofar, it seems to work great, even in non-English countries, something I am always worried about.
The Intel AMT serial port is much like any other serial port, but it has a PCI device identifier that is not normally known to Microsoft Windows and so, Windows does not know what to do with this device. On Intel’s web site, there is an SOL driver available. The serial driver itself is just a small .INF that tells Microsoft Windows to load and use the standard serial driver. In fact, one can manually force the standard Windows serial driver to be used for this device. You need to go in the device manager and pick a driver from the list, select Microsoft as the manufacturer and you will see it. Even if it’s possible, I don’t recommend it because the DTK code will no longer recognize that COM port as being the AMT port, it’s going to work but will have the wrong name for auto-detection.
Lastly, if someone needed to know if a computer is AMT enabled without having to load any drivers, one way to do it would be to detect the presence of the Intel AMT serial port. It is always present even when AMT is un-provisioned, and it can’t be turned off, unless AMT is disabled entirely in MEBx. This can be a good way to figure out if you need to start considering a computer for AMT setup.