10.2.3-1 Feedback

Within engineering constraints imposed by sound-powering, the system should provide in-phase feedback to the user.

Additional Information:
In control room use, sound-powered phones are generally of the headset variety (either one or two earphones and a boom microphone in an assembly fitting on the head). Sound-powered phones are independent of external power, a feature of value in emergency use. Additionally, the headset configuration, used with conveniently located plug-in jacks, provides mobility for the user when moving to remote locations (back panels or outside the control room).