Morse code encoded the same way (A, O, E, I, T, M, N, R, K, etc.). Bulgarian alphabet contains 30 characters, which exactly match all possible combinations of 1, 2, 3, and 4 dots and dashes. Russian requires 1 extra character, "Ы" which is encoded with 5 elements. During early World War I (1914–1916), Germany briefly experimented with 'dotty' and 'dashy' Morse, in essence adding a dot or a dash at the end of each Morse symbol. Each one was quickly broken by Allied SIGINT, and standard Morse was restored by Spring 1916. Only a small percentage of Western Front (North Atlantic
Morse code silence. ATIS (Automatic Transmitter Identification System) uses Morse code to identify uplink sources of analog satellite transmissions. An important application is signalling for help through SOS, "". This can be sent many ways: keying a radio on and off, flashing a mirror, toggling a flashlight, and similar methods. SOS is not three separate characters, rather, it is a prosign SOS, and is keyed without gaps between characters. Some Nokia mobile phones offer an option to alert the user of an incoming text message with the Morse tone "" (representing SMS or Short Message Service). In addition, applications are now available