TIA ANSI/TIA-5050 PDF

This Standard establishes receive volume control requirements and testing methods for wireless handset telephones that support narrowband and/or wideband audio interfaces for individuals without hearing loss and for individuals with hearing loss who may or may not use a hearing device.

The methods in this standard use conversational gain, which, in summary, is the measure of the acoustic output level of speech from a device relative to the acoustic level that would be present in a face-to-face conversation with two people 1 meter apart.

NOTE: Other acoustic receive features may be available such as additional amplification, tone control, automatic gain control, etc. ANSI/TIA-4953-B contains performance requirements for output levels and tone control operation for high gain amplified devices for individuals with hearing loss.