
Also document that `ProtectClock` blocks access to serial line. I couldn't found out why this is the case, but faxgetty complains about the device file not being accessible with `ProtectClock=true`.
Also document that `ProtectClock` blocks access to serial line. I couldn't found out why this is the case, but faxgetty complains about the device file not being accessible with `ProtectClock=true`.