The S110 Softdevice is a BLE peripheral only stack and can have one concurrent link at the same time. So you can have one connection at the time. You can store pairing/bonding information and rotate through multiple, but only one at the time. You can however also be in a connection with one and at the same time broadcast or use non-connectable advertising to send broadcast to any phone or tablet that is in your proximity.
The S310 is based on the S110 for BLE functionality, so it can only have 1 BLE connection at the time. You can have ANT connections concurrently with the BLE connection. So for the S310 you can have one BLE link and up to 8 ANT links concurrently.
