 ATI2


              Data flow in error-control mode

                                                  +--------------------------+
                                                  |  Strip start, stop bit   |
              DTE (PC)                   RS232    |  Add start, stop bit     |
                ͻ   Chars sent      Ŀ   |    Ŀ                |
                       > TXD |>     Ŀ   |
                ͼ  <  RXD <|     <Ŀ    |
              Ŀ Chars received         |                      |
                                      |                      |
                                            |                  |
     +--------------------------------------------+                        |
     |                     Ŀ                                         |
     |                                                                   |
     |     Blocks received                        Octets received        |
     |   >      >Ĵ    |
     |    <      <|Ĵ   |
     |     Blocks sent                        Octets sent            |
     |                                                          |
     |                   Framing      Octets       Ŀ              |
     |                                received                       |
     |                               >     >    |
     |                              <     <   |
     |                                  Octets sent                      |
     |                                                               |
     |                                            Data Compression         |
     |                                                                     |
     +---+-+-----------------------------------------------------------------+
                       Ŀ         Async-to-Sync Conversion
          >Ĵ Modulation       
                        
         
         
                         Ŀ
         <Ĵ DeModulation    
                          






       Chars    Datas receive from or send to DTE (PC). They are formated as
                7,E,1 or 7,O,1 or 8,N,1 etc.

       Octets   Datas receive or send to remote modem in error control mode.
                They are compressed if data compression was enabled.

       Block    Framed Octets. They are delimited by the unique bit pattern
                "01111110" known as a flag.



       Chars Sent         Characters DTE has sent to modem
       Chars Received     Characters modem has sent to DTE
       Octets Sent        Data (bytes) have sent to remote modem
       Octets Received    Data (bytes) have received from remote modem
       Blocks Sent        Blocks have sent to remote modem
       Blocks Received    Blocks have received from remote modem
       Blocks Resent      Blocks have resent due to remote modem request. If
                          there were many Blocks Resent, you may experienced
                          problems on the line or protocol incompatibility.
       Max Outstanding    Maximum blocks received without acknowledge remote modem
       Max Block Size     Maximum octets contain in a block
       Retrains Requested The number of times local modem request retrain
       Link Duration      By minutes
       Retrains Granted   The number of times remote modem request retrain
       T401 Timeouts      For protocol maintainace, modems probably recovered.
       T402 Timeouts      For protocol maintainace, modems probably recovered.
       FCS Errors         Errors in frame (block) checksum. If there were many
                          FCS Errors, you may experienced problems on the line.
       Round Trip Delay   By T (1/2400 sec)
       Xmitter Underrun   For modem's processor power measurement
       Receiver Overrun   For modem's processor power measurement
       Disconnect Reason  Only four reasons areavailable
                          Local Hang Up
                          Remote Hang Up
                          Carrier Lost
                          Resent Expiration (others)






