busy signal
短语词组
- busy back signal 忙回信号;占线信号
- busy flash signal 占线信号;占线闪光信号
- busy tone signal 占线信号;忙音信号
- subscriber -busy signal 用户忙信号;用户占线信号
- busy -flash signal 占线闪光信号
- busy signal system 明显损失制
- busy signal generator 忙音发生器
- group busy signal 群占线信号
- audible busy signal 音响占线信号;可闻忙音讯号;忙音信号 返回 busy signal