The Internal Microphone System uses a unidirectional mic element. Since the mic is on a gooseneck, you are able to position the mic to get the sound that you want. There is a white dot on the windscreen that denotes the acitve side of the mic.
A single AA battery powers the mic. The jack acts as a "switch" to turn the battery "on" when a plug is inserted in the jack.
This is a low impedance microphone with a one conductor (hot and ground) unbalanced line. You can use a standard mono instrument cable for many applications. But some equipment, (P.A. boards) require XLR. In this case you will need to use a 1/4" to XLR adaptor.
When plugged directly into a P.A board, the Microphone may sound best through the XLR mic input. If you are using a mono cable and having problems with a weak signal, you need to connect to a XLR input.