Telephone communications with several commercial respirators.

Previous work showed that telephone communications while wearing military respirators degraded both word comprehension and recognition speed. In addition, electronic amplification of the speech diaphragm signal had shown no advantage to the extra hardware. This experiment was performed to test effects of different configurations of commercially available respirators on telephone communications accuracy and speed. Twelve pairs of subjects were separated into different rooms and communicated by telephone. Modified rhyme-test words were presented by computer to the speaker, who transmitted the word by telephone to the listener. During the first replication, subjects were given no instruction about telephone communications procedure. During the second replication subjects followed a communications protocol that instructed them when to move the telephone handset from their ears to their mouths. Results showed that the protocol uniformly improved communications accuracy without incurring any extra time penalty. Word comprehension was still twice as fast without a respirator as with a respirator. Accuracy with the protocol nearly equaled the no respirator control value for most respirators tested.