The "USB link" refers to the method of flashing firmware directly from a USB drive plugged into the TV's port. ASANO 42LF110T, TP.SK506S.PB802, USB Firmware Software
Firmware update and serial communication via USB interface Hardware: TPsk506SPB802 (Embedded control / RF module) Interface: USB (Type-C or Micro-USB, depending on carrier board) Purpose: Reliable firmware programming, debugging, and configuration access