Stands for Infrared Data Association, which is the trade association for defining infrared standards, and is a common data link layer protocol for use with PDAs communicating with a PC over an infra-red link. See:

DG -- I believe the proper way to display the irdaDeviceID member of the SOCKADDR_IRDA struct is to use the MAC address style:

    SOCKADDR_IRDA *irdaaddr;
    char formatedId[12];
    /* Device ID. */
    sprintf(formatedId, "%02x-%02x-%02x-%02x",
            irdaaddr->irdaDeviceID[0], irdaaddr->irdaDeviceID[1],
            irdaaddr->irdaDeviceID[2], irdaaddr->irdaDeviceID[3]);

But I'm not sure.. Does anyone know the accepted manner?

See also infrared and OBEX