Government agency of India, MEITY, has released the criteria for the series formation on the Phase IV devices (all 12 of them) for CRS, in the document they have released, they have also specified the maximum number of models that can be in a series according to the classification of the devices.
Some of the devices included are:
3. Item No. 47: Keyboard
• Same Enclosure except for differences of decoration parts
• Same rated Input voltage
• Same PCB design layout
• Same IP rating
Note: Maximum 10 models can be included in a series
7. Item No. 51: Wireless Headphone and Earphone
• Same type (over the ear or in the ear )
• Same type of charging (USB /charging case/wireless).
• Same rating of battery [registered batteries for headphone/earphone].
• Same rating of a battery of charging case [registered batteries for charging case], if applicable.
• Same Enclosure material except for differences of decoration parts.
• Same IP rating
• Registered power bank/adapter with the same output rating to the input of headphones/earphones.
• The change in location of buttons may be accepted subject to the lab ensures that it does not have an effect the safety.
Note: Maximum 10 models can be included in a series