The Macintosh Quadra is a family of personal computers designed, manufactured and sold by Apple Computer, Inc. from October 1991 to October 1995. The Quadra, named for the Motorola 68040 central processing unit, replaced the Macintosh II family as the high-end Macintosh model. The first models were the Quadra 700 and Quadra 900, both introduced in October 1991. The Quadra 800, 840AV and 605 were added through 1993. The Macintosh Centris line was merged with the Quadra in October 1993, adding the 610, 650 and 660AV to the range. After the introduction of the Power Macintosh line in early 1994, Apple continued to produce and sell new Quadra models; the 950 continued to be sold until October, 1995. The product manager for the Quadra family was Frank Casanova who was also the Product Manager for the Macintosh IIfx. Models The first computers bearing the Macintosh Quadra name were the Quadra 700 and Quadra 900, both introduced in 1991 with a central processing unit (CPU) speed of 25 MHz. The 700 was a compact model using the same case dimensions as the Macintosh IIci, with a Processor Direct Slot (PDS) expansion slot, while the latter was a newly designed tower case with five NuBus expansion slots and one PDS slot. The 900 was replaced in 1992 with the Quadra 950, with a CPU speed of 33 MHz. The line was joined by a number of "800-series" machines in a new minitower case design, starting with the Quadra 800, and the "600-series" pizza box desktop cases with the Quadra 610. In 1993, the Quadra 840AV and 660AV were introduced at 40 MHz and 25 MHz respectively. They included an AT&T 3210 Digital signal processor and S-Video and composite video input/output ports, as well as CD-quality microphone and audio output ports. The AV models also introduced PlainTalk, consisting of the text-to-speech software MacinTalk Pro and speech control (although not dictation). However all of these features were poorly supported in software and a DSP was not installed in later AV Macs, which were based on the more powerful PowerPC 601 - a CPU powerful enough to handle the coprocessor's duties on its own. Branding Apple hired marketing firm Lexicon Branding to come up with the name. Lexicon chose the name Quadra hoping to appeal to engineers by evoking technical terms like quadrant and quadriceps. The Quadra name was also used for the successors to