A mobile communication device 10 for converting between alphanumeric data and TTY formatted data. A conversion table 20, 40 is stored in a memory associated with microprocessor 16 of mobile 10. Microprocessor 16 converts alphanumeric characters input by a user to TTY formatted data for transmission in digital mode. TTY formatted signals that are received by mobile 10 are converted to alphanumeric data by TTY decoder 26 and microprocessor 16 for display on mobile display 14. In analog mode, tone generator 44 produces a Baudot tone formatted signal for transmission from mobile 10. Tone detector 46 detects Baudot tone formatted signals received in analog mode. Microprocessor 16 converts the Baudot tone formatted signals to alphanumeric data for display on display 14.