language difficulties. Each word is accented on thecapitalized syllable. You should memorize the phoneticalphabet and use it along with correctly pronouncednumbers, as described earlier in chapter 3, for alltelephone and lookout reports.REVIEW 1 QUESTIONQ1. You are manning the sound-powered telephonein a repair locker. DC central calls and wants theserial number of the P-100 pump (23DBCX14)in your repair locker. How should you say thisnumber over the phone?SOUND-POWERED TELEPHONESLearning Objectives: When you finish this chapter,you will be able to—R e c o g n i z e t h e c o m p o n e n t s o f t h esound-powered telephone.Identify the procedures to follow when usingsound-powered telephones.Sound-powered phones are just what the nameimplies—phones that operate on your voice power andrequire no batteries or external electrical power source.When you speak into the mouthpiece, the soundwaves of your voice cause a diaphragm to vibrate. Thevibrations are transferred from the diaphragm through adrive rod to an armature centered in a wire coil. The coilis located in a magnetic field supplied by two permanentmagnets. Movement of the armature in the magneticfield causes a current to be induced into the coil. Thecurrent then is transmitted to a receiver (the earpiece)where the process is reversed, and the person at the otherend of the circuit hears the same sounds youtransmitted.The mouthpiece and earpiece, though shapeddifferently, function in the same manner and thus can beused interchangeably. You can talk into an earpiece andhear through a mouthpiece. This feature is important toremember not only in the event of a breakdown of one orthe other pieces but also because undesired noises canbe fed into the system through an earpiece turned awayfrom your head.THE HEADSETFigure 4-1 shows a headset type of sound-poweredtelephone. The mouthpiece is suspended from a yokethat is attached to a metal breastplate. The earpieces areconnected by an adjustable band. The mouthpiece andearpiece are connected by wire from a junction box onthe breastplate. The plug cord is also connected into thisjunction.The headset is delicate and can be easily damaged.When you pick up the set to put it on, hold the entire unitin your left hand. You will find the headset is hung overthe transmitter’s supporting yoke and the lead wires arecoiled.To put the gear on—1. Unhook the right side of the neck strap from thebreastplate, put the strap around your neck, andthen fasten it to the breastplate again.4-2Student Notes:Figure 4-1.—Headset.
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
