History of the Arabic alphabet the same. After all this, there were only 17 letters that were different in shape. One letter-shape represented 5 phonemes ("b t th n" and sometimes "y"), one represented 3 phonemes ("j ħ kh"), and 5 each represented 2 phonemes. Compare the Hebrew alphabet, as in the table at . A similar ambiguity occurs in the German Fraktur font, in which the Roman alphabet uppercase letters I and J look the same but are officially different letters. The Arabic alphabet is first attested in its classical form in the 7th century. See PERF 558 for the first surviving Islamic Arabic
Prosigns for Morse code efficient telegrapher/telegraphist. The procedure signs below are compiled from the official specification for Morse Code, ITU-R M.1677, International Morse Code, while others are defined the International Radio Regulations, including ITU-R M.1170, ITU-R M.1172, ITU-R M.1677-1, and the International Code of Signals, with a few details of their usage appearing in ACP-131, which otherwise defines operating signals, not procedure signals. For the special purpose of exchanging ARRL Radiograms during National Traffic System nets, the following prosigns and signals can be used, but many of them do not have equivalents in any other definition of Morse code signals, including the ITU-R and