^^As they said, all of these drives are electrically IDE/ATAPI, but only the 1400 used any sort of a standard connector. Every other PowerBook until the Lombard/iBook used a custom internal connector (usually a ribbon cable) to connect the drive to the PB module interface board. Everything after used the same relatively standard connector; the problem was finding a drive that would cooperate with the signalling used by the computer (specifically bus mastering), and with a similar faceplate (where required). I've had no success in swapping a Teac or Samsung drive into a Lombard/Pismo module, but Matsushitas usually work.