It was just the telephony which solved the effort to convey human speech directly and to long distances. The Bell’s invention enabled literally a revolution also in military conception of long-distance transmission of messages. It is the same as in case of telegraphy, that the best advantage of the telephone is the fact that it is two-sided communication means. Unlike the telegraphy, there is no need to have specially trained operator and the devices are evidently simpler. However, rather easy possibility of monitoring (spying) of the enemy conversation remains the worst disadvantage. It was stated after the war that the damages caused by monitoring (spying) of the telephone network from the side of the enemy were higher than its utility.