Abstract: An adaptor to connect handheld computing devices to peripheral devices and to provide connectivity between various versions of handheld computing devices, such as the Palm PDA and peripheral devices. The top end of the adaptor has a first inserting connector, which is connected to the handheld computing device via an insertion slot, and the bottom end of the adaptor has a second inserting connector, which is connected to the connection interface of the peripheral device. Thus, the adaptor of the present invention can connect a peripheral device to various types of handheld computing devices, which may have a different interface connection.