GEMTEK RADIO SERIAL COMMUNICATION PROTOCOL      1999.6.25 Atsushi Umeshima 
============================================================================

    This document describes the serial communication protocol used by
    GemTek serial line radio module. This information is not official. 
    Rather, it is the result of individual analysis. Please.  Do *not* 
    contact GemTek to ask questions about this information. 
   

SERIAL PROTOCOL
===============

    * 9600baud 8 bit stop bit 1 Non parity
    * No flow control
    * RTS on
    * DTR on


COMMAND FORMAT
==============

Commands generally follow this format:
    0x1D 0x23 0xXX ... 0x23 (hex)
That is, a command flag (0x1D 0x23) followed by command parameters,
followed by a 0x23.


COMMAND LIST
============

  above the line: data sent to the device
  ---------------------------------------------
  below the line: data recieved from the device

  ASCII code values are quoted.
  All other values are hex.

  POWER ON 
  ========
    1D 23 01 23
    -----------    

  Comment:
    Power on the device.
    No answer returns.

  POWER OFF
  =========
    1D 23 02 23
    -----------    

  Comment:
    Power off the device.
    No answer returns.


  SET FM FREQUENCY
  ================
    1D 23 05 'XXX' 23
    -----------------------------------------
                      1D 23 06 23 1D 23 07 23 
  Comment:
    XXX is the value converted by the following formula.
      (frequency(MHz) - 76.0) * 20
    The converted value is padded on the left with zeros.(i.e. 76.1MHz -> '002')
    From '000'(76.0MHz) to '640'(108.0MHz) is valid.

  SET AM FREQUENCY (valid only for AM/FM radio e.g. GemTek RADIOMAN)
  ==================================================================
    1D 23 09 'XXX' 23
    -----------------------------------------
                      1D 23 06 23 1D 23 07 23 
  Comment:
    XXX is the value converted by the following formula.
      (frequency(kHz) - 531) / 9
    The converted value is padded on the left with zeros.(i.e. 1134kHz -> '067')
    From '000'(531kHz) to '119'(1602kHz) is valid.

  HEALTH CHECK?
  =============
    1D 23 08 23
    -----------------------
                1D 23 07 23
  Comment:
    Original Windows software uses this command once per second.
    I don't know what's the meaning.

  HEALTH CHECK?
  =============
    1D 23 08 23
    -----------------------
                1D 23 04 23
  Comment:
    Sometimes radio module answers "1D 23 04 23" instead of "1D 23 07 23".

  HEALTH CHECK?
  =============
    1D 23 08 23
    -----------------------
                1D 23 06 23
  Comment:
    Sometimes radio module answers "1D 23 06 23" instead of "1D 23 07 23".
    (reported by Jorge Ventura)
