Hi Hemasatya,
The Remote control for your SoundTouch 120 is intended to emulate the basic functions of most other commonly branded devices. Make sure that you have tried all the variations on the LG control code, following the process
described in this video.Even with the most compatible code selected, not all functions may map perfectly to your ST120 remote. In particular, new Smart-TV functions are often something you will still need to use the TV remote for as each brand implements these very differently from their standardized Power, input and channel +/- functions.
Thank you for your question.