a selectively removable module , such as a pcmcia card , inserted into a host computer system , such as a notebook computer , is provided that has a electrical interface between the module circuitry and the host computer circuitry , a wireless data channel is implemented between the module circuitry and the host computer system circuitry that is independent of the electrical interface . this wireless communications channel is implemented entirely within the confines of the external housing of the host computing system . one embodiment uses an infrared led or emitter to transmit infrared signals from the module circuitry to an infrared sensitive phototransistor located within the host and electrically connected to the host circuitry . likewise , an infrared led or emitter located within the host computer housing and electrically connected to the host computer circuitry transmits an infrared signal to a infrared sensitive phototransistor located on the module and electrically connected to the module circuitry to complete a bi - directional , wireless data transmission channel . the internal wireless data transmission channel allows large data throughput without interfering with the operation or capacity of the normal electromechanical interface between the module circuitry and the host computer system . such a wireless data communications channel finds particular use in implementing a speakerphone on a host computer system , such as a notebook computer , having a microphone and speaker but using the circuitry in a pcmcia modem card to manage and control the speakerphone .