subfamilies occurred, such as: some flat-pack devices (e.g. 7400W) and surface-mount devices, some of the faster CMOS series (for example 74AC), a few low-power TTL devices (e.g. 74L86, 74L9 and 74L95) have a different pin-out than the regular (or even 74LS) series part. five versions of the 74x54 (4-wide AND-OR-INVERT gates IC), namely 7454(N), 7454W, 74H54, 74L54W and 74L54N/74LS54, are different from each other in pin-out and/or function, Second sources from Europe and Eastern Bloc Some manufacturers, such as Mullard and Siemens, had pin-compatible TTL parts, but with a completely different numbering scheme; however, data sheets identified the 7400-compatible number as an aid to recognition. At the time the 7400 series was being made, some European manufacturers (that traditionally followed the Pro Electron naming convention), such as Philips/Mullard, produced a series of TTL integrated circuits with part names beginning with FJ. Some examples of FJ series are: FJH101 (=7430) single 8-input NAND gate, FJH131 (=7400) quadruple 2-input NAND gate, FJH181 (=7454N or J) 2+2+2+2 input AND-OR-NOT gate. The Soviet Union started manufacturing TTL ICs with 7400-series pinout in the late 1960s and early 1970s, such as the K155ЛA3, which was pin-compatible with the 7400 part available in the United States, except for using a metric spacing of 2.5 mm between pins instead of the pin-to-pin spacing used in the west. Another peculiarity of the Soviet-made 7400 series was the packaging material used in the 1970s–1980s. Instead of the ubiquitous black resin, they had a brownish-green body colour with subtle swirl marks created during the moulding process. It was jokingly referred to in the Eastern Bloc electronics industry as the "elephant-dung packaging", due to its appearance. The Soviet integrated circuit designation is different from the Western series: the technology modifications were considered different series and were identified by different numbered prefixes – К155 series is equivalent to plain 74, К555 series is 74LS, К1533 is 74ALS, etc.; the function of the unit is described with a two-letter code followed by a number: the first letter represents the functional group – logical, triggers, counters, multiplexers, etc.; the second letter shows the functional subgroup, making the distinction between logical NAND and NOR, D- and JK-triggers, decimal and binary counters, etc.; the number distinguishes variants with different number of inputs or different number of elements within a die – ЛА1/ЛА2/ЛА3 (LA1/LA2/LA3) are 2 four-input / 1 eight-input / 4 two-input NAND elements respectively (equivalent