Transmission of Background Conversation by the TA-341 Telephone Set. The Problem and Proposed Solutions

The purpose of this experiment was to examine the degree to which the TA-341 telephone set picks up background conversation and to test some alternative handset and headset configurations to determine whether hardware either currently in use by the Army or other commercially available equipment could offer a practical solution to the problem. Eight passive devices were examined in detail and were evaluated in terms of their ability to reject background conversation without affecting the intended communication. None proved successful. Therefore, an active device-an electronic program expander (EPEX)-was built and tested. It demonstrated a high degree of success in meeting the requirements against which the passive devices had been tested. Details both of the operational characteristics and of the circuit design of EPEX are reported. (Author)