A cable for communicating digital or analog signals between connectors at its opposite ends has means for indicating to an installer who has access to one end of the cable which connector is connected at the opposite end of the same cable. A light source is mounted in each connector that is powered by a battery in the connectors and can be turned on from a switch in the connector at the opposite end. The light source is configured to radiate light both transversely from its connector for an indicator function and also longitudinally from its connector for an illumination function. Implementation with logic circuits, microcontrollers and/or other semiconductor devices allows for a variety of embodiments.