how many phone can bluetooth device linked concurrently

[qoboty]

Bluetooth device,use S110,can linked one phone,like example ble_app_uart, How many phone linked concurrently? Thank you!

[Stefan Birnir Sverrisson]

The S110 is a peripheral softdevice, which means the phone needs to be an central in order to communicate with it. A peripheral device can only maintain one connection at a time. If you let however nRF51 act as a central by using S120 softdevice, then you can maintain up to 8 links to 8 different peripherals concurrently, e.g. to 8 phones that act as peripherals. The S110 can however maintain a single connection and concurrently broadcast in non-connectable mode. Further ideas are on this thread

[qoboty]

Thank you, Can device by using S120 or S130 link two different phone passively?

[Stefan Birnir Sverrisson]

S120 and S130 can act as centrals and thereby maintain connect connection to multiple phones if the phones support peripheral role. IOS supports both peripheral and central roles. Android has supported only central role but it seems that they start support peripheral role with Android 5.x. Android 4.x only supports central role

[Stefan Birnir Sverrisson]

S120 can maintain up to 8 concurrent peripheral links. For S130: "Up to 4 simultaneous active connections: up to 3 in the Central role, along with up to 1 in the Peripheral role."

[qoboty]

If two Android phone act as central role, NRf51822 bluethooth is the peripheral device, which softdevice shall I choose S130,or something else ?

[Stefan Birnir Sverrisson]

S110 is sufficient for the peripheral role. If you however intend to switch roles at some point, choose S130, as it is both peripheral and central. S130 requires more recources, both ROM and RAM, so if you dont need both central and peripheral, choose S110.