Using laid cables, soldiers would connect one telephone to another or connect to a switchboard to reach different units. In combat, the Battalion Command Post would use these telephones to reach other companies. With the phone down, one would crank it up, press a button to get the attention of the other line, and then lift the telephone. Then they would move a switch, speak, and let go to allow the other line to reply. Some soldiers found that if they whistled at a specific pitch, they could make the other end ring.