Novation also introduced an internal direct-connect modem, the Apple-CAT II, which plugged into an expansion slot in an Apple II computer. Due to the internal connection, the Apple-CAT II was able to feature a full range of dialing commands, and could report a wide range of call progress tones (BUSY, REORDER, etc.) that many modems still lack today. These operations were handled directly by software on the host computer; the modem set certain registers when tones were heard on the line, and by timing when these registers were set or cleared, the software could determine what was happening on the line.