Mediatek Usb Vcom drivers & Cdc drivers .Any difference?

[gobi3725]

Hi ,can anyone tell me what is difference between Mediatek(MTK) Usb Vcom drivers & CDC drivers.Both seem to have the same functions,flashing firmware,transfer files etc.
And why the need to install both drivers in PC to connect & communicate with Mediatek powered Android devices via a USB connection.

 

[B. Diddy]

Welcome to Android Central! Which phone, and which PC? What Windows version is it running?

When you connect your phone via USB to your PC, it prompts you to install those drivers?