Smartphone as peripheral

[KV]

Can the smart phones or tablets be configured as a peripheral? If yes, why is this not common? Are there any limitations if a tablet/phone is configured as a peripheral device?

We are looking to see if we can make our custom device as scanner and tablet/phone as an advertiser.

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Yes they can.

It's not common because originally Android was not supporting Peripheral role and still today it's up to handset manufacturer and for some (typically older Android 5) devices it's not supported.

Second reason is power consumption: BLE was originally (and probably still is) used by deeply embedded "peripheral" devices like sensors (smart watch and other wearables, home appliances) and these are supposed to have long-lasting batteries while mobile phones and tablets are anyway expected to be charged every +-24 hours so bigger power consumption with BLE GAP Central role won't be a big problem.

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...(2/2) contains MAC address as well.

TL;DR if you care about privacy you should run some feasibility, otherwise it is better to be Observer/Central but even if you broadcast modern devices should hide your real MAC against untargeted tracking attacks