1. BUSYTONE：X0 影响连线的状态码,从原CONNECT XXXX变为CONNECT;而忽略连线及拨号时不侦测拨号音(Dial Tone)及忙音(Busy Tone). X4 Modem侦测拨号音及忙音. (出厂设置).
Yn 间号(Space)断线指令(非同步制)&F1 重新读取第1组的参数设定值.
2. 忙音
2. signal for the busy line：盲目投资blind investment, haphazard investment | 忙音signal for the busy line | 漫游roaming service
3. engaged signal：energy spectrum 能谱 | engaged signal 忙音 | engine analyzer 马达分析机
4. Busy Tone BT：忙时试呼次数 Busy Hour Call Attempt BHCA | 忙音 Busy Tone BT | 毛刷 Brush