XLR type connectors are mainly used with microphones and mixing units. These type of connectors have 3 pins.

1. The earth 2. Positive signal 3. Negative signal

Jacks

Jack connectors come in two sizes - 1/4" and 1/8" which are sometimes known as a mini-jack.
Both sizes are wired the same, and come in mono or stereo types.

The mono type jack is split into two sections; the tip and the sleeve. The tip is the pointed end of the plug, with the sleeve being the rest of it. You will find that guitar cables and microphone leads will have mono jack type connectors.

A stereo jack, which is also known as a TRS jack, is a little different to a mono jack, and is split into three sections - a tip and a sleeve, with a ring between the two, which is where the TRS abbreviation comes from. Stereo jacks can be used to carry either balanced or stereo signals.

Stereo jacks can be used as speaker cables carrying balanced signals, or as headphone leads carrying stereo signals.

You will probably be familar with these connectors as they can be used for both audio and video signals, and are often found in home enterainment systems, like hifi's.

Phono connectors are sometimes known as RCA connectors.

You will no doubt be very familiar with USB connectors as they often use to connect devices like printers and keyboards to your computer. Each end of a USB connector is different, the larger end is known as the "A" connector while the smaller connector is known as "B". End "A" would be the connector that fits into your computer, with "B" being the end that connects to the external device.

USB 1.0 was only capable of transfer rates of 12Megabits per second (1.5 Megabytes) - which is not nearly fast enough for audio recording. However, USB 2.0 (which is used by newer computers) is capable of 480Mbps (60 Megabytes).

Note that the vast majority of USB audio or MIDI interfaces use USB 2.0, which provides a fast enough data transfer for low-latency recording.

MIDI leads are 5-pin connectors and are used for communication between devices such as keyboards or synthesizers. Pins 1 and 3 have no set use however some MIDI equipment uses them for other functions.

Used in the same manner as USB, it is often used to connect external devices to your computer. It provides fast rates of data transfer (up to 800Mbps) for recording multiple tracks at once.

Firewire (also known as IEEE 1394) cable connectors come in several different types depending on the type of Firewire port - using 4, 6 or 12 pins.