A person having GST registration pertains to cable operator services, can he do any trading business without taking GST registration and also not mentioning the same in to the above GSTIN
No, you can not do that... There is no requirement to take seprate registration Compulsorily but you have to use this GST registration, if not taking seprate GSTIN.
You also required to charges GST on your outward Supply of trading business and have to pay tax their on as per tax liability calculated in prescribed manner.
CAclubindia
