和其他建立在串口配置文件之上的配置文件一样，被更低层蓝牙通信协议实现的虚拟串行链接对使用DUN配置文件的应用程序是透明的。

Like other profiles built on top of the serial port profile, the virtual serial link created by the lower layers of the Bluetooth protocol stack is transparent to applications using the DUN profile.

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基于此，服务发现应用配置文件规定任何应用程序能够在任何要连接的蓝牙设备上找出有哪些有效服务。

Based on this, the service discovery application profile requires that any application be able to find out what services are available on any Bluetooth device it connects to.

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照这样，这个配置文件支持了旧的应用程序使用蓝牙就像是用串口链接，且不需要任何修改。

As such, the profile allows legacy applications to use Bluetooth as if it were a serial-port link, without requiring any modification.

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