a minimum of features, which could be inserted into a docking station to provide the system with extra video memory, storage space, connectors, and could be connected to a monitor. PowerBook 500 series 1994 saw the introduction of the Motorola 68LC040-based PowerBook 500 series, code-named Blackbird. These models of PowerBooks were much sleeker and faster than the 100 series, which they replaced as the mid and high-end models. The 500 series featured DSTN (520) or active-matrix LCD displays (540 and 550), stereo speakers, and was the first computer to use a trackpad (although a similar technology had been included on the pioneering Gavilan SC 11 years earlier); it was also the first portable computer to offer built-in Ethernet networking. The PowerBook 500 series was the mainstay of the product line until the PowerBook 5300. The 500 series was the first PowerBook to feature PCMCIA slots, although this was an optional feature that required the user to sacrifice one of the two available battery slots to house the PCMCIA expansion cage. The PowerBook 500 series was released as Apple was already moving its desktop machines to the PowerPC processor range, and a future upgrade was promised from the start. This came in 1995, as an Apple Motherboard containing a 100 MHz 603e processor and 8 MB of RAM (which snapped into a slot containing the previous 25 or 33 MHz 68040 processor and the 4 MB of RAM on the previous daughterboard). At the same time Newer Technology offered an Apple-authorized 117 MHz Motherboard, which was more popular than the Apple product, and optionally came without any RAM. The company later offered 167 MHz and 183 MHz upgrades containing more memory and onboard cache memory to improve performance. Nonetheless, the internal architecture of the 500 series meant that the speed increase provided by the 100 and 117 MHz upgrades was, for most users, relatively small. The 500 series was completely discontinued upon the introduction of its replacement the PPC-based PowerBook 5300, with the PowerBook 190 replacing the 500 as the only 68LC040 PowerBook Apple offered. PowerPC-based models The PowerBook 5300, while highly anticipated as one of the first PowerPC-based PowerBooks (along with the PowerBook Duo 2300c, both released on the same day), had numerous problems. In its 5300ce incarnation with a TFT of 800x600 pixels, Apple offered a 117 MHz PPC, 32 MB of on-board RAM, and a hot-swappable drive bay.