A device for interconnecting and multiplexing a plurality of interfaces is disclosed. In the preferred embodiment, three serial communications ports are interfaced such that any two may be interconnected for communications. A novel circuit comprising a plurality of buffers is employed to allow selection of the interconnection scheme by a controller. The design is scalable and is characterized by low cost, low printed circuit board area requirements, and graceful function. In the preferred embodiment, a PDA, wireless transceiver, and cradle interface of a personal communications device are effectively interconnected and multiplexed.