Cordless Telephones: A Threat to Hearing:

Several patients with documented permanent sensorineural hearing losses secondary to the use of cordless telephones have been evaluated. In the interests of saving space and weight, these units have the ear receiver double as the ringing or bell device. The output of the bell on all of the units we have tested to date has been in the 140-dB range on the A scale. In each instance, the patient held the telephone against the ear when ringing occurred, and in three instances a loud extraneous crack was transmitted. Unlike regular cord-type telephones, these devices have no automatic gain control in the receiver circuit.