In theory,the Bluetooth adapter can connect up to 7 Bluetooth devices at the same time.As for how many can be connected at all,only by having it tested can you know it.

In general,the computer,connected to the Bluetooth headset, can listen to songs and simultaneously transfer files to the Bluetooth mobile phone.Not only the computer can do it, but also the mobile phone can connect more than two Bluetooth devices at the same time.

The Bluetooth primary device can communicate with up to seven devices, though not all devices can achieve this maximum. The roles can be converted between devices through protocols, that's, the slave devices can also be converted to master devices. For example, if a headset initiates a connection request to a mobile phone, it is naturally the primary device as the initiator of the connection, but may then operate as a secondary device.

Bluetooth exists in many products, such as phones, tablets, media players, robot systems, handheld devices, laptops, gamepads, and some high-quality headphones, modems, watches and so on. Bluetooth technology is useful for transmitting information between two or more devices in close proximity under low bandwidth conditions. Bluetooth is commonly used for telephony voice transmission (such as Bluetooth headsets) or byte data transmission (file transfer) of handheld computer devices.