A very robust and latching connector commonly used to carry balanced audio signals such as the outputs from microphones or line-level devices. An XLR is a type of connector developed by US manufacturer, Cannon, and used widely in professional audio systems.
The company’s original X-series connector was improved with the addition of a latch (Cannon XL) and a more flexible rubber compound surrounding the contacts to improve reliability (Cannon XLR). The connector format is now is available in numerous configurations, from many different manufacturers, and with several different pin configurations. Standard balanced audio interfaces — analogue and digital — use three-pin XLRs with the screen on pin 1, the ‘hot’ signal on pin 2 and the ‘cold’ signal on pin 3.