Abstract: The present invention relates to a device and a method for connecting a mobile phone handset to an external keyboard. A multimedia card slot interface is included in the portable keyboard of the present invention, which can be incorporated to the original interface of the handset. In the meantime, a microprocessor and a random access memory are also included in the keyboard. After sending an interrupt command from the handset to the keyboard, by scanning the keyboard, whether the key is pressed or not is determined by the microprocessor and the key value is stored in its own random access memory. When the key value is stored in the random access memory, an interrupt command is sent to the handset by the keyboard. After the handset is ready, the key value will be transferred to the handset via the multimedia card slot interface.