socket层是网络子系统的标准API，它为各种网络协议提供了一个用户接口。

The sockets layer is the standard API to the networking subsystem and provides a user interface to a variety of networking protocols.

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第三章对蓝牙协议，以及蓝牙用户模式、蓝牙的通讯过程、蓝牙主机控制接口(HCI)信息交换命令的数据格式进行了阐述。

In the Chapter 3, it expounds the Bluetooth protocols, the mode Bluetooth users, the process of Bluetooth communication and Bluetooth exchange specific information of Host Control Interface (HCI).

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系统中用户任务的网络传输程序是基于UDP编写的，它包括了网卡驱动函数， 协议层操作函数和用户接口函数。

The network transmit program in user's tasks of the system is based on UDP. It includes network card driving function, protocol layer handling function and user interface function.

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