The notebook can be connected to multiple Bluetooth devices at the same time, and generally a Bluetooth can support 7 devices at the same time. But the supported Bluetooth devices need to be different types, for example, the mouse and the headset are two different types of devices. Therefore, the connection of Bluetooth keyboard, Bluetooth mouse, Bluetooth headset can be connected to the PDA to transfer files. Bluetooth® is a wireless technology standard that enables short-range data exchange between fixed devices, mobile devices and building personal domain networks (using UHF radio waves in the ISM band of 2.4-2.485 GHz). Bluetooth technology was originally created by giant Ericsson in 1994 as an alternative to RS232 data lines. Bluetooth can connect multiple devices, overcoming the problem of data synchronization. Bluetooth host devices can communicate with up to seven devices in a piconet (a temporary computer network using Bluetooth technology), although not all devices can reach this maximum. The roles between devices can be switched by protocol, and the slave device can also be converted to the master device (a headset that initiates a connection request, as the initiator of the connection, is naturally the master device, but may then operate as the slave device). Data transfer can take place at any time between the main device and other devices (except for broadcast modes, which are rarely applied). The master device can select the slave device to access; Typically, rapid transitions can be made between devices in a rotational manner. Personal computers without built-in Bluetooth for operating system applications can communicate with Bluetooth devices through Bluetooth adapters. Some desktops and, more recently, most laptops have a built-in Bluetooth radio, but those that don't need an external adapter for Bluetooth communication, usually a small USB dongle. Unlike earlier versions of IrDA, which required a separate adapter to connect each device, Bluetooth enables communication between a computer and multiple devices through a single adapter. Apple has been using Bluetooth since the MacOSX v10.2 in 2012. On Microsoft platforms, Windows XP Service Pack 2 and SP3 versions provide native support for Bluetooth 1.1, 2.0, and 2.0+EDR. Earlier versions required users to install a Bluetooth adapter driver instead of directly supporting Bluetooth. Microsoft's own Bluetooth dongle (included with its Bluetooth computer devices) does not have an external drive, so Windows XP Service Pack 2 is required. Windows Vista RTM/SP1 or Windows Vista SP2 with wireless feature pack compatible with Bluetooth 2.1+EDR. Windows 7 is compatible with Bluetooth 2.1+EDR and Inquiry Response (EIR). The Windows XP and Windows Vista/Windows 7 Bluetooth stacks provide native support for the following Bluetooth protocols: PAN, SPP, DUN, HID, HCRP. The Windows XP stack can be replaced by a third-party stack that supports other protocols or newer Bluetooth versions. The Windows Vista/Windows 7 Bluetooth stack supports third-party protocols and does not require it to replace Microsoft's stack. Linux has two commonly used Bluetooth stacks, BlueZ and Affix. Most Linux core programs include the BlueZ stack, which was first developed by Qualcomm. The Affix stack was developed by Nokia. FreeBSD supports Bluetooth starting with version 5.0. NetBSD supports Bluetooth starting with version 4.0. Its Bluetooth stack is also plugged into the OpenBSD port. The short link broadcast technology (later renamed Bluetooth) was originally developed by Nils Rydbeck, CTO of Ericsson Mobility, in Lund, Sweden. The aim was to develop a wireless headset based on two inventions published in 1989 (Dr. Johan Ullman's SE 8902098-6, released June 2, 1989, and SE 9202239, released July 24, 1992). Nils Rydbeck left the specification work to Tord Wingren and the development work to Jaap Haartsen and Sven Mattisson. They work for Ericsson in Sweden. This specification is based on frequency hopping technology. Reference: Bluetooth - Encyclopedia