A breakout box is a device used to sniff traffic on a (usually) rs-232 line. Normally, they just look like odd straight through cables, that branch off into two additional cables. One connects the TX, and connects to RX on the one branch; and the other goes from the RD line to the RD line on the other branch. Thus, one of the branches is out, and the other in. There are software packages which do basicly the same thing, one of which is called "Breakout", that usually require two serial ports; one incoming, one outcoming, and sniff that.