控制电话信令 完成忙碌 等待 回铃音振铃等-Signaling complete control over telephone ring so busy waiting ringback tone

基于FPGA的信令音产生程序，包括拨号音，忙音，振铃音等-FPGA-based signaling tone generation process, including dial tone, busy tone, ring tones, etc.

一个电话用户信令控制器设计，电话接续过程中控制忙音，回铃音和振铃输出。-A telephone users signal controller design.Phone in the process control in busy tone, back to LingYin and ringing output.