Serial.sys and serenum.sys

Serial.sys typically controls the COM ports (typically named COM1, COM2, and so on) located on the case of a PC that is running Windows.

SerCx and SerCx2

Starting with Windows 8, SerCx is a system-supplied component that supports serial communication between integrated circuits on a printed circuit board.(印刷电路板上的继承电路)

Starting with Windows 8.1, SerCx is superceded by SerCx2. SerCx2 has many improvements over SerCx to reduce the size and complexity of serial controller drivers.