The audio data is always sent to the modem slightly faster than it can play it, so the modem may buffer a small portion of it and play it smoothly with no clicks or pops caused by delays in the computer's operating system. For example, during playback of an 8 kHz audio file at 8-bit resolution (which creates 8,000 bytes, or 80,000 bits when including start/stop bits, per second), the data must travel over the serial port at a minimum of 115,200 bits per second. (115,200 bit/s is the first setting of a typical computer serial port that's greater than 80,000.) In addition, due to some extra overhead involved in doubling DLE bytes in the stream (mentioned below), a small amount of extra bandwidth is mandatory to allow for this.
