All kinds of satellite set-top box upgrades
The router, hard disk, ADSL, broadband, etc., can have their firmware updated or cracked.
Cell phones, XBOX360, GPS serial communication, auto-detection, DVD flash, etc.
And write STC SCM, NXP SCM, Renesas microcontroller, NEC microcontroller, etc.
Simple serial communication, using the commonly used super terminal serial port debug tool.
Electronic enthusiasts can use the USB signal to turn TTL signal.