more accessible connectors, unlike the variable mixture of internal—and sometimes virtual—and external connectors found in consumer-grade sound cards. Sound devices other than expansion cards Integrated sound hardware on PC motherboards In 1984, the first IBM PCjr had a rudimentary 3-voice sound synthesis chip (the SN76489) which was capable of generating three square-wave tones with variable amplitude, and a pseudo-white noise channel that could generate primitive percussion sounds. The Tandy 1000, initially a clone of the PCjr, duplicated this functionality, with the Tandy 1000 TL/SL/RL models adding digital sound recording and playback capabilities. Many games during the 1980s that supported the PCjr's video standard (described as Tandy-compatible, Tandy graphics, or TGA) also supported PCjr/Tandy 1000 audio. In the late 1990s, many computer manufacturers began to replace plug-in sound cards with an audio codec chip (a combined audio AD/DA-converter) integrated into the motherboard. Many of these used Intel's AC'97 specification. Others used inexpensive ACR slot accessory cards. From around 2001, many motherboards incorporated full-featured sound cards, usually in the form of a custom chipset, providing something akin to full Sound Blaster compatibility and relatively high-quality sound. However, these features were dropped when AC'97 was superseded by Intel's HD Audio standard, which was released in 2004, again specified the use of a codec chip, and slowly gained acceptance. As of 2011, most motherboards have returned to using a codec chip, albeit an HD Audio compatible one, and the requirement for Sound Blaster compatibility relegated to history. Integrated sound on other platforms Various non-IBM PC compatible computers, such as early home computers like the Commodore 64 (1982) (and by extension Commodore 128 in 1985) and Amiga (1985), NEC's PC-88, and PC-98, Fujitsu's FM-7 and FM Towns, Sharp's X1 and X68000, Acorn's BBC Micro, Electron and Archimedes, Atari's 8-bit home computers, ST and Falcon, Amstrad's CPC, later revisions of Sinclair's ZX Spectrum, the MSX, Apple's Macintosh and IIGS, and workstations from manufacturers like Sun, Silicon Graphics and NeXT have had their own motherboard-integrated sound devices. In some cases, most notably in those of the Macintosh, IIGS, Amiga, C64, PC-98, SGI Indigo, X68000, MSX, Falcon, Archimedes, FM-7 and FM Towns, they provide very advanced capabilities (as of the time of manufacture), in others they are only minimal capabilities. Some of these platforms have also had sound cards designed for their bus architectures that cannot be used in a standard PC. Several Japanese computer platforms, including the