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                                W A V E C O M
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OPEN AT V1.10
Updated : April 23th, 2002

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                              Content of this file
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Sample application n°3 (Half Duplex Data) description

I.      Changes
II.     Application description
III.    Application States
IV.     Remote Task Environment specificity



   
I - Changes
===========

* 01/11/06  -   V1.00
  Initial revision.

* 02/04/23  -   V1.10
  New Wavecom sample library.
  The "AT+CRC" command now returns "+CME ERROR: 600".



II - Application description
===========================

 The user shall download the application on two Wavecom products equipped with
a SIM card (supporting DATA subscription). A specific "AT+DATA" command has
been defined to initialize a data call between one product, considered as
Master, and antoher one considered as Slave. The master product then sends 256
data blocks to the Slave, and then releases the call.

        (Test Command)
        AT+DATA=?
        +DATA: (20)
        OK
        
        (Parameters Command)
        AT+DATA=<number>
                
            <number> : phone number of the Slave product.
            
        If <number> is correct, this module is considered as Master.
        The application then opens the Data and V24 flows, and calls the
        other product with the "ATD" command.
        
        As the other product receives the indication of a data call, it is
        considered as Slave. The application then opens the Data and
        V24 flows, and answers to the Master with the "ATA" command.
        
        On the Master product, as the "CONNECT" response comes, the application
        begins to send data blocks :
        
            "Sent from Master [X]" for Master
            X range value is [0.255]
            
        On the Slave product, when a data block is received on the Data flow, it
        sends this block to the serial link :
            
            "Rec {YYY}\r\n"
            where YYY is the data block received.
            
        When the Master has sent all its data blocks, the application releases
        the call. Then both products close the V24 and Data flows.
        
 This command is only available is IDLE state, once the "+WIND: 4" indication
has been issued.
 
 
 
III - Application States
========================
 
 * CRC settings
 
          ********
       +->* IDLE *
       |  ********
       |    |
       |    |   first IDLE
       |    |
       |    V
       |  ************
       +--* CRC INIT *  Send the "AT+CRC=1" command, to receive +CRING 
          ************  indications
                    
 
 * MASTER states

          ********
      +-->* IDLE *
      |   ********
      |     |
      |     |   AT+DATA command
      |     |
      |     V
      |   ***************
      |   * MASTER SEND *   Open flows
      |   ***************   Send "ATD" command
      |     |               On CONNECT response, set a 0.2s cyclic timer
      |     |                -> On timer expiry, send a data block to Slave,
      |     |                   and display a "M" character.
      |     |   
      |     |   When all data blocks are sent
      |     V
      |   *******
      +---* ATH *   Release the call, close the flows and return to IDLE
          *******
                    
 
 * SLAVE states

          ********
      +-->* IDLE *
      |   ********
      |     |
      |     |   "+CRING" data call indication
      |     |
      |     V
      |   *******
      |   * ATA *   Open data and V24 flows, Answer the call
      |   *******   
      |     |
      |     |   CONNECT response
      |     |
      |     V
      |   *************
      |   * SLAVE REC *   On data block received, send it to V24 flow
      |   *************
      |     |
      |     |   When the Master has sent all data blocks, close the flows and
      +-----+   return to IDLE



IV - Remote Task Environment specificity
========================================

In remote task mode, sending a large amount of data on the V24 flow may cause
some troubles. So, on the slave module, all data blocks received from the Data
flow are displayed as a response in remote task mode ; on the master module,
the "M" character is also displayed as a response.