Disable discovering and advertisement after the connection is established

[joao pimenta]

Considering that as soon as the connection is established (GAP Peripheral device receives CONNECT_REQ packet) and advertising is over. Is it possible once the connection is established to make the device not discoverable and keep this connection running? Does the BLE allows this?

[endnode]

This is misunderstanding of my previous comment. Once there is connection established, by default Peripheral (advertiser) automatically stops advertising and just follows the connection. What do you mean by discoverable? If you mean visible as advertiser then normally then it should disappear (unless the device wants to and starts advertising simultaneously to existing link). If you mean hidden then of course that's not possible, person equipped with any radio analyzer will see the packets of ongoing link.

Note that according to BT SIG Core specification v4.0-4.1 Peripheral device should support only one connection link so it can only start non-connectable advertisement. However in V4.2 this limitation was lifted so devices can optionally support multiple Peripheral connections (and latest Nordic BLE stacks on nRF52 chips do support it). This of course remains in BT 5.0 because it's backward compatible.