WHAT THEY ARE & HOW THEY WORK - Sound powered telephones, handsets or headsets, contain electro-mechanical transducers that convert voice directly into electrical energy. This signal is sent down to a two-wire line and converted back into voice at the other end. The phones require no batteries, amplifiers or power supplies, emit no electro-magnetic or radio-frequency interference, present the user with no shock hazard and yet are capable of transmitting clear voice communications over distances up to five miles.

SOUND POWERED TELEPHONES, either headsets, handsets, or a combination of the two, can be used in many applications including concrete pumping, crane operations, assembly work on complex systems such as airframes, in-plant maintenance, wire pulling by electricians, sports spotter systems, rescue operations of many types, communications underground such as in train and subway tunnels and in tanks, production line balancing and many others. In short, sound powered telephones are useful in any situation where two or more people must communicate who cannot hear or cannot see each other, when clear, reliable communications are imperative.

COMPARED TO conventional amplified systems, hardwired and wireless, sound powered telephones are less costly, both to buy and maintain. They are simple to hook up and use. They are not affected by heat, cold or humidity, surrounding concrete or steel structures, as is frequently the case with wireless systems, and are not subject to instant obsolescence. They require little or no maintenance, are simple to repair when they do, and they are always there, on and ready to go.

HOW TO OPERATE SOUND POWERED TELEPHONES - It's simple! Just hook them together and talk. Do not ground the connecting cables. If you run wires close to powerful electro-magnetic fields use shielded cables. Wire phones together in parallel, not series, and most importantly, because the phones are voice powered and the output of a phone is directly proportional to the input from your voice, speak directly into the microphone.