Fig. 141. Diagram showing how to connect up two telegraph instruments. The circles on the tables represent the binding posts of the instruments.
Make another ground connection near the left-hand instrument; that is, take a wire long enough to reach from some pipe or radiator to the left-hand telegraph instrument, bind one bare end of this wire firmly to a clean part of the pipe and bring the other end toward the instrument. Before attaching this other end to the free binding post of the left-hand instrument, be sure to open the switch beside the telegraph key by pushing it to your right. Close the switch on the other instrument. Now attach the free ground wire to the free binding post of your telegraph instrument, and press the key. Does the other instrument click? If not, disconnect the ground wire and examine all connections. Also press the sounder of each instrument down and see if it springs back readily. It may be that some screw is too tight, or too loose, or that a spring has come off; tinker awhile and see if you cannot make the instrument work. If you are unable to do so, ask for help.
Fig. 142. Telegraphing across the room.
Figure 141 is a diagram of all the connections.
When you want to telegraph, open the switch of the instrument you want to send from and close the switch of the instrument which is to receive the message.
Holding the key down a little while, then letting it up, makes a "dash," while letting it spring up instantly, makes a "dot."
Practice making dots and dashes. Telegraph the word "cat," using the alphabet shown on the next page. Telegraph your own name; your address.
Here is the Morse telegraph code in dots and dashes:
Letters
