看到「Quiet for Android - TCP over sound」這個給 Android 用的專案，就是以前的撥接數據機嘛... 在直接拉線對連時連速度都還蠻像的：
Quiet's provided audible mode transfers at approximately 7kbps. In cases where two devices are connected over a cable (via 3.5mm jack) it can run in cable mode, which transfers at approximately 64kbps.
拿來做一些 (邪惡的) 事情？