To enable a data communication while charging a portable communication terminal by providing a connecting means for performing data communication to the portable communication terminal and a connecting means for executing data communication to an external data terminal.

This device is equipped with a rectifier circuit 1, a circuit for charging 2, a power source connection part 3 and a charging control circuit part 4. A data connection part 5 is an interface for transmitting data of an external data terminal to a PHS slave machine. A serial data control part 6 takes an interface with the external data terminal, for example, a personal computer. A PHS access forum standard (PIAFS) control part (an adapter part) 7 realizes a PIAFS of a layer 2 transmission procedure for performing a data transmission of 32 kbps by using the PHS. Then, the serial data from the external data terminal is converted by the PIAFS control part 7 to a PIAFS frame by way of the serial data control part 6 and transmitted to the PHS slave machine by the data connection part 5 while the PHS slave machine is being charged.