additional digit indicates the constructive variant. For the 1973 and 1980 standards the variant digit is appended with a dash after the designation (e.g. К712РВ2-1 and Б533ТМ2-2, respectively). For the 2000 and 2010 standards the variant digit follows immediately after the package designation N (e.g. 5862ПФ1Н4 and 1374МХ01Н1, respectively). Manufacturer designation A manufacturer designation was introduced only with the 2000 standard. As part of the type designation the manufacturer is required only for a second-source integrated circuit that was "developed and produced according to an independently developed design and technological documentation, and corresponding to the technical requirements of the originally developed original microcircuit". Manufacturer logos are more common. Other manufacturers which as of 2016 used a version of the Soviet integrated circuit designation include NTC Module, MCST, ELVEES Multicore, Fizika, Sapfir, NPK TTs, and Progress, all of them in Moscow, as well as PKK Milandr, Soyuz, and NIITAP in Zelenograd, SKTB ES Voronezh, Proton and Proton-Impuls Oryol, Planeta Novgorod, NIIEMP Penza, Eltom Tomilino, Krip Tekhno Alexandrov, DELS Minsk, Kvazar Kyiv, Krystal Kyiv, Elektronni Komponenti Ivano-Frankivsk, Dnepr Kherson, and Foton Tashkent. Other markings Although not strictly part of the designation, a number of markings are often found on integrated circuit packages: Military acceptance here means that the integrated circuit can be used in applications where its failure would be catastrophic and where repair or exchange is difficult or impossible (e.g. aerospace applications). For mask-programmed devices (e.g. gate arrays, mask-programmed single-chip microcontrollers, mask ROMs) a three- or four-digit mask number follows the type designation (e.g. К1801ВП1-014). For bare chips a one-digit constructive variant identifier follows the type designation. A date code is usually printed on the package. In the early 1970s the date code consisted of a Roman numeral for the month and a two-digit year (e.g. IX 72). Later the month was given as one or two digits (e.g. 5-73 or 0386). In the late 1980s most plants switched to a 4-digit code with a 2-digit year followed by a 2-digit month (e.g. 8909) or a 2-digit week (e.g. 9051). Overall, the date code format was not strictly enforced. Several series of integrated circuits (e.g. 1408, 1821) bore an IEC 60062 letter and digit code (e.g. A1 for January 1990). Romanization The Romanization of Russian is standardized, but there are at least 12 standards to choose from. Fortunately, the Soviet integrated circuit designation uses a subset of the Cyrillic alphabet where