taglinefilesource code
send_break2212drivers/char/cyclades.csend_break(info, HZ/4); /* 1/4 second */
send_break2219drivers/char/cyclades.csend_break(info, arg ? arg*(HZ/10) : HZ/4);
send_break1864drivers/char/serial.csend_break(info, HZ/4);  /* 1/4 second */
send_break1871drivers/char/serial.csend_break(info, arg ? arg*(HZ/10) : HZ/4);