这是一个优秀的Telcom公司开发的Q921商用协议栈，已在很多项目中使用并验证。实现了完整的Q921 LAPB和LAPD协议栈-This is an excellent Telcom developed Q921 commercial protocol stack has been used in many projects and verify. To achieve a complete Q921 LAPB and LAPD protocol stack

实现LAPD帧的校验、插值和去插值函数,既封包和解包处理-LAPD frame to achieve the calibration, interpolation and the interpolation function to