Show for code practice in radio communication those who have a longing to know the code used in radio communication will find the circuit shown sh own in figures I 1 and 2 useful in the practice of sending and receiving dots and dashes the system Is especially applicable to radio clubs school classes and other 0 organizations desiring a means for group practice the material needed la Is a buzzer capable of producing a high frequency az mom 1111 FIG 1 note a telephone induction coll coil a switch a key and pair of phones per person and the necessary batteries by arranging the parts as aa shown in figure F 2 the be controlled by arty any one of the keys ays eys only tile the keys kes buzzer coil binding posts etc need be mounted on tile the top of the lie operating table while fill all the wiring Is made on the under side mom VMS al j em COK av mom FIG 2 A As may be seen irom from the schematic diagram in figure 1 the secondary key phone circuit 14 a series parallel one allowing provision for additional operating positions the signal being heard in till all the phones in this way lt it in ia possible to maintain intercom mun leation between the several receiving points by putting the buzzer in a continuously operated circuit the tone produced will be more constant than if the several keys were used to interrupt the buzzer circuit also by placing the keys in the secondary side of the circuit there will be no appreciable prec preci able lable lag or key thump in the signals as transmitted |