7526 DCT Reference


Control Command Details

This section describes the 7526 DCT communications control commands listed at the beginning of this chapter. The proper format for each command is specified, and additional information is provided when necessary.

Notes:

  1. In the command descriptions, parentheses, commas (,) or spaces ( ) are not part of the text or data stream transmitted or received by the terminal; they are used for clarification in the examples.
  2. Parameters in braces are optional.
  3. The format of commands sent to the DCT are not dependent on the current operating mode. Enhanced mode commands can be sent to a DCT in 7525 Compatibility mode. l.
  4. CMD 0&mdash.Reset Terminal

    This command has two options: Warm Reset and Cool Reset.

    In Warm Reset (type = 0) the terminal is reset. If completion is normal, the terminal becomes operational and files need not be re-downloaded.

    In Cool-Reset mode (type = 1) this command resets the terminal, halts running applications, and reinitializes memory allocations. Power-on Self Test is run, and if completion is normal, the download of files is requested by responding to a poll with a DC1 character on the communications network. Files must be downloaded, however it is not necessary to reconfigure the terminal's address, baud rate, parity setting, or number of data bits.

    The format for this command is:

         => STX, addr, addr, 0, {type}, CS1, CS2, ETX
    The optional type controls how the reset is completed. There is no terminal response. The first status character is set to 1, and the terminal becomes operational when reset is complete.

    If the type is omitted, command CMD 0 operates as it does with the 7525, which is a Warm Reset (type = 0), allowing compatibility with that machine.

    CMD 1&mdash.Transmit Terminal Status to Terminal Controller

    The format for this command is:
         => STX, addr, addr, 1, CS1, CS2, ETX
         <= STX, data, CS1, CS2, ETX
    The data portion consists of a string of 12 ASCII characters that define the terminal status as follows:
         Character            Description
         ---------      ------------------------------------------------
             1          0  Normal state
                        1  First status request since POST completed
    2 0 Last command executed correctly 1 Last command did not execute correctly 2 Last broadcast was received OK

    3 0 Required file download is present 1 File download required

    4 0 Terminal is In Service 1 Terminal is Out of Service

    5 0 All commands since last CMD 1 executed correctly 1 Command failure occurred since last CMD 1 (Always = 1 in 7525 Compatibility mode)

    6, 7 cc Identifies command for status information Character 7 is a blank (ASCII space) for single character commands

    8, 9 00 Last command OK 0f Last command OK (f = file 0&mdash.a, c, e) 10 Invalid command 1f Invalid command (f = file 0&mdash.a, c, e) 20 Invalid text or format 2f Invalid text or format (f = file 0&mdash.a, c, e) 3f File overrun (no space) 4f File not initialized 5f Record not found (f = file 0&mdash.a, c, e) 69 Invalid attempt to initialize file 9 6f Invalid attempt to initialize file f (f = file 0&mdash.a, c, e) 7f Still processing command (f = files 0-a, c, e) 80 Last command ignored because terminal in wrong state

    10, 11 ff Identifies current mode and polled data file Af = Interactive/buffered mode Bf = Buffered mode Cf = Interactive mode

    12 0 No data in transaction queue 1 Data exists in transaction queue

    CMD 2&mdash.Write to Terminal Display

    The format for this command is:
         => STX, addr, addr, 2, text, CS1, CS2, ETX
         <= ACK or NAK
    The text refers to ASCII characters to be displayed in the sequence sent. Space characters appear as blanks on the display. Normally, the data written to the display remains until Timer B count has expired as specified in File 0.

    Display time-out can be avoided by using an ASCII Device Control 2 (DC2) character as the first character of the text.

    To prevent disturbing normal transaction display messages, this command is handled only during terminal idle state.

    Notes:

    1. Idle refers to a terminal state in which the terminal is not executing a transaction program or a CFR; the terminal may be receiving commands and sending replies, but is waiting for the operator to initiate a transaction.
    2. When displaying on the 7526 DCT, Model 100, the first 16 characters of the message text are displayed. On the Model 200, the message wraps to the second line of the two-line display after 40 characters. An E04 error occurs when more data is written than can be displayed on either model.
    3. Programs written for the 7525 must be re-evaluated to ensure the message text can be accommodated on the 7526 Model 100 16-character display.
    4. Record separators are not allowed as part of the text. l.
    5. CMD 3&mdash.Transmit ROM Microcode Version and Revision to Terminal Controller

      The format for this command is:
           => STX, addr, addr, 3, CS1, CS2, ETX
           <= STX, data, CS1, CS2, ETX

      Enhanced Mode

      The data is a string of four ASCII characters defining the terminal ROM microcode where: For example, 0101 means version 01, revision 01.

      7525 Compatibility Mode

      The data is a string of two ASCII characters defining the terminal ROM microcode where:

      CMD 4&mdash.Set Terminal Time and Date

      The format for this command is:
           => STX, addr, addr, 4, text, CS1, CS2, ETX
           <= ACK or NAK
      The text refers to 12 ASCII numeric characters in the following format using the 24-hour clock: YYMMDDHHMMSS.

      When setting the clock from a host computer, the 7526 DCT terminal must first be set out of service. This prevents conflict between the set-clock command and an input transaction which may be in progress.

      The correct sequence is:

      1. Set terminal out of service (CMD A)
      2. Set clock (CMD 4)
      3. Set terminal in service (CMD A)

      CMD 5&mdash.Activate Terminal Audible Tone

      The format for this command is:
           => STX, addr, addr, 5, text, RS, CS1, CS2, ETX
           <= ACK or NAK
      The text refers one ASCII numeric character (1-9) that relates to a tone duration. The value of the text multiplied by 0.5 second determines the duration of the tone.

      To prevent disturbance during normal transactions, this command is handled only during terminal idle state while the terminal is offline or out of service.

      Note:

      Tone is asynchronous, and if back-to-back CMD 5 commands are executed, the tone duration is that of the second command.
      .

      CMD 6&mdash.Transmit Terminal Features to Terminal Controller

      The format for this command is:
           => STX, addr, addr, 6, CS1, CS2, ETX
           <= STX, data, CS1, CS2, ETX

      Enhanced Mode

      The data is a string of five ASCII characters that define the terminal's features, as follows:

      7525 Compatibility Mode

      The data is a string of four ASCII characters as defined for the 7526 DCT and are as follows:

      CMD 7&mdash.Transmit Terminal TOD to Terminal Controller

      The format for this command is:
           => STX, addr, addr, 7, CS1, CS2, ETX
           <= STX, data, CS1, CS2, ETX
      The data refers to the current terminal time and date using the same format as CMD 4 (YYMMDDHHMMSS).

      A CMD 1 status request returns "80" for characters 8 and 9 to indicate invalid terminal state, if the terminal has not been downloaded. If the time has not been initialized with CMD 4, the returned data will be zeroes.

      CMD 8&mdash.Specify Current Polled Buffer or File

      The format for this command is:
           => STX, addr, addr, 8, text, RS, CS1, CS2, ETX
           <= ACK or NAK
      The text contains one or three ASCII characters that specify the currently polled buffer or file and the number of data records to be transmitted on a poll. The following ASCII characters are valid parameters for the text portion of CMD 8: When the terminal is switched to buffered mode, the terminal controller must poll all the buffered transaction records out of the terminal before the terminal switches back to interactive mode.

      Note:

      The terminal returns invalid command status to CMD 8 if execution is attempted when the DCT is in service. To preclude conflict, the following sequence is required:
      1. Set terminal out of service (CMD A)
      2. Execute CMD 8
      3. Set terminal in service (CMD A)
      If there are no files loaded on the terminal, the terminal returns invalid state status to CMD 8.

      CMD 9x&mdash.Terminal Text or Data File Management

      The 9x commands are used for initializing and managing up to 12 text or data files. Records in these files can be of variable length. An ASCII record separator (RS) is used between records and following the last record. This series of commands allow the terminal controller to perform the following:
      • CMD 9A&mdash.Send file status to terminal controller
      • CMD 9B&mdash.Initialize text file
      • CMD 9C&mdash.Load text file
      • CMD 9D&mdash.Delete text records
      • CMD 9E&mdash.Erase validation files
      • CMD 9F&mdash.Transmit data file contents to terminal controller
      Status should be queried (CMD 1) after each text or data file command (9x) to verify if the command executed properly.

      CMD 9A&mdash.Send File Status to Terminal Controller

      The format for this command is:
           => STX, addr, addr, 9A, f, RS, CS1, CS2, ETX
           <= STX, f, data, CS1, CS2, ETX
      The f represents the file number (0-9, a, e)

      The data portion consists of a fixed length string of ASCII characters that indicate the status of the specified file.

      Enhanced Mode

      The format is: aaaaaauuuuuudp

      Where:

      • aaaaaa = Number of bytes reserved by previous CMD 9B (000001-065535).
      • uuuuuu = Number of bytes not used
      • d = Text type specified
        • 0 = Compacted numerical text
        • 1 = Non-compacted alphanumeric text
      • p = Type of text specified
        • 0 = Non-polled file
        • 1 = Polled file.
      Notes:
      1. In the enhanced mode, six digits are returned and the maximum file size is 65535 bytes, except for file 9 which can occupy all remaining memory.
      2. To obtain status for File c, use CMD MA.
      l.

      7525 Compatibility Mode

      The format is: haaahuuudt

      Where:

      Note:
      P999 is the largest value returned in the 7525 compatibility mode, however, more RAM may be in use.
      .

      CMD 9B&mdash.Initialize Specified Text File

      The format for this command is:
           => STX, addr, addr, 9B, f, text, RS, CS1, CS2, ETX
           <= ACK or NAK
      The f is the file number (0-9, a, e)

      The text is a fixed length string of ASCII characters that initializes a specified text file, reserves file space, and defines file characteristics.

      Enhanced mode or 7525 compatibility mode may be used at anytime regardless of the operating mode set with CMD P or File 0 Record 00 offset 203.

      Enhanced Mode

      The format is: lllllldtrsfrrrrr

      Where:

      7525 Compatibility Mode

      The format is: haaadt

      Where:

      Notes:
      1. The DCT must be set out of service (via CMD A) before CMD 9B can be executed.
      2. Files 0, 8, a, and e must always be alphanumeric.
      3. Initializing file 0 implies losing all files. This is never allowed with transactions in buffer file 9. Reinitializing of other files is allowed when their size is equal to or smaller than the loaded file.
      4. To initialize File c, use CMD MB. l.
      5. CMD 9C&mdash.Load Text File

        The format for this command is:
             => STX, addr, addr, 9C, f, text, RS, CS1, CS2, ETX
             <= ACK or NAK
        The f represents the file number (0-8, a, e)

        The text is variable length ASCII data.

        Text records are loaded into a specified file (0&mdash.8, a, e). Repeat the CMD 9C string to complete loading the file. Text records may be variable in length and can be in multiple communications records and may have a maximum length, including the control characters, of:

        • 255 characters for RS-485 asynchronous host/server connection
        • 512 characters for TCP/IP Ethernet host/server connection
        An ASCII record separator (RS) must be entered between the text records and at the end of the last text record transmitted. The characters 32 (20h) to 255 (FFh) are valid in text files.

        The following example sends text records 1234, 123, and 12345 to File 3.

        • 9C31234RS123RS12345RS
        CMD 9C is valid only with non-polled files. An attempt to load text to File 9 will be rejected, and status character 8 is set to 1.

        Notes:

        1. The DCT must be set out of service (via CMD A) before CMD 9C can be executed.
        2. To load File c, use CMD MC. l.
        3. CMD 9D&mdash.Delete Text Records

          CMD 9D is used for deleting text records from a validation text file. More than one record can be deleted with one CMD 9D. The limiting factor is the maximum record length. An ASCII record separator (RS) must be inserted between records and at the end of the last record transmitted. If the text record is not found in the file, then status character number 8 is set to 5.

          The format for this command is:

               => STX, addr, addr, 9D, f, text, CS1, CS2, ETX
               <= ACK or NAK
          The f represents the file number (2-7).

          The text refers to variable length records followed by RS.

          The following format is an example of deleting the records JOHN and MARY from file 2. :

               9D2JOHN(RS)MARY(RS)
          CMD 9D is valid only with validation files. An attempt to delete records from any other file will be rejected, and status character 8 is set to 1.

          Notes:

          1. When a record is deleted from a file, the file records are restructured to use the space left by the deleted record. Therefore, if record position is critical (such as prompt messages), this command should not be used.
          2. If two records are identical, only the first one is deleted.
          3. If multiple records are specified in CMD 9D, only those found in the file will be deleted. When it is important to delete a particular record, only one record should be specified in CMD 9D, followed by a status command (CMD 1) to verify the deletion. l.
          4. CMD 9E&mdash.Erase Validation File

            CMD 9E erases all text records in a specified text file. The empty file remains initialized and can be loaded again via CMD 9C.

            The format for this command is:

                 => STX, addr, addr, 9E, f, RS, CS1, CS2, ETX
                 <= ACK or NAK
            The f represents the file number (2-7). If f = 0 then files 2-7 are erased at once.

            The following format is an example of deleting all records in file 2:

                 9E2
            CMD 9E is valid only with validation files. An attempt to erase text from files other than 2-7 will be rejected, and status character 8 is set to 1.

            CMD 9F&mdash.Transmit Data File Contents to Terminal Controller

            The format for this command is:
                 => STX, addr, addr, 9F, f, text, RS, CS1, CS2, ETX
                 <= STX, data, CS1, CS2, ETX
            The f represents the file (0&mdash.9, a, e).

            Enhanced Mode

            The text is the record number of the block (0000-9999).

            The data consists of a block of bytes that is transmitted to the host.

            The size of the block is determined by the host communication's buffer size specified in Extended File 0. If the buffer size is more than 128 bytes, the same data can be part of two records.

            7525 Compatibility Mode

            The text is the record number of the 128 byte block (000-999).

            The data consists of a block of 128 bytes that is transmitted to the host.

            An ASCII carriage return (CR-hex 0D) follows the last data record in the file.

            Notes:

            1. If the specified text file has not been initialized, the terminal responds with an ASCII cancel character (CAN-hex 18) and the status character number 8 is set to 4. The following is an example:
            2.      <= STX, CAN, CS1, CS2, ETX
            3. When reading Files 0-8, a, and e, only data previously loaded can be retrieved.
            4. The entire allocated space of File 9 can be retrieved.
            5. This command is intended for use with files containing only ASCII data.
            6. If attempting to read data beyond the end of the file, an ASCII carriage return (CR-0D) is returned. l.
            7. CMD A&mdash.Set Terminal State

              The format for this command is:
                   => STX, addr, addr, A, text, CS1, CS2, ETX
               
                   <= ACK or NAK (for commands A1 and A0)
                 or
                   <= DC3 (for command A1X when a download is not needed)
                 or
                   <= DC1 (for command A1X when a download is needed)
                 or
                   No response (for command A0X )
              The text is one or two ASCII characters:
              0
              Set the terminal Out of Service, thus preventing use by the workers.
              1
              Set the terminal In Service, allowing use of the terminal functions.
              0X
              Tell the terminal it is not allowed to send unsolicited data transactions to the host/server. This does not affect the online/offline status.
              1X
              Tell the terminal it is allowed to send unsolicited data transactions to the host/server. This does not affect the online/offline status.
              In the out of service mode, the display will show the OUT OF SERVICE message. The terminal will be out of service and input transactions will not be accepted. Any transaction or CFR executing at the time the CMD A0 is received will be aborted.

              Note:

              Commands A1X and A0X are only allowed when the 7526 is operating with the host/server connection set to TCP/IP Ethernet (10base2 or 10baseT).

              CMD B&mdash.Positive Response from Terminal Controller

              The format for this command is:
                   => STX, addr, addr, B, text, {position}, RS, CS1, CS2, ETX
                   <= ACK or NAK
              The text is a string of ASCII characters used to control the audible tone and write messages to the display. STX and ETX cannot be used in the text string.

              The position consists of an identifier to signify that cursor positioning information follows, and a row and column value.

              Enhanced Mode

              The first character controls audible tone:
              • 0 = No tone, prompt timeout after Timer B
              • 1 = Tone, prompt timeout after Timer B
              • 2 = No tone, no prompt timeout
              • 3 = Tone, no prompt timeout
              Additional text characters define the display source:
              • #HELLO {@rrcc} = Write message HELLO to the display at an optional row and column position
              • $fllll {@rrcc} = Write record at llll in File f to the display at an optional row and column position
                • f = File number (2-8)
                • llll = Record location (0000-9999) within the file
                • {@rrcc} = Optional cursor positioning information
                  • @ = Indicator that row and column information follows.
                  • rr = Row number (01-02) on the display.
                  • cc = Column number (01-40) on the display.

              7525 Compatibility Mode

              The first text character has the same function as the Enhanced Mode.

              Additional text characters define the display source:

              • #ACCEPT {@rrcc} = Write message ACCEPT to the display at an optional row and column position
              • $fll {@rrcc} = Write record ll in File f to the display at an optional row and column position
                • f = File number (2-8)
                • ll = Record location (00-99) within the file.
                • {@rrcc} = Optional cursor positioning information
                  • @ = Indicator that row and column information follows.
                  • rr = Row number (01-02) on the display.
                  • cc = Column number (01-40) on the display.
                The following example activates audible tone for a valid transaction and writes record 3 of File 4 to the display:
                • B3$403
              Note:
              CMD B is processed only when the terminal is waiting for an interactive response (when the DCT is waiting for a response in interactive mode to acknowledge receipt of a transaction record by the terminal controller).

              CMD C&mdash.Negative Response from Terminal Controller

              The format for this command is:
                   => STX, addr, addr, C, text, {position}, RS, CS1, CS2, ETX
                   <= ACK or NAK
              The text is a string of ASCII characters used to control the audible tone and write messages to the display. STX and ETX characters cannot be used in the text string.

              The position consists of an identifier to signify that cursor positioning information follows, and a row and column value.

              Enhanced Mode

              The first character controls audible tone:
              • 0 = No tone, prompt timeout after Timer B
              • 1 = Tone, prompt timeout after Timer B
              • 2 = No tone, no prompt timeout
              • 3 = Tone, no prompt timeout.
              Additional text characters define the display source:
              • #HELLO {@rrcc} = Write message HELLO to the display at an optional row and column position
              • $fllll {@rrcc} = Write record at llll in File f to the display at an optional row and column position
                • f = File number (2-8)
                • llll = Record location (0000-9999) within the file.
                • {@rrcc} = Optional cursor positioning information
                  • @ = Indicator that row and column information follows.
                  • rr = Row number (01-02) on the display.
                  • cc = Column number (01-40) on the display.

              7525 Compatibility Mode

              The first text character has the same function as the Enhanced Mode.

              Additional text characters define the display source:

              • #ACCEPT {@rrcc} = Write message ACCEPT to the display at an optional row and column position
              • $fll {@rrcc} = Write record ll in File f to the display at an optional row and column position
                • f = File number (2-8)
                • ll = Record location (00-99) within the file.
                • {@rrcc} = Optional cursor positioning information
                  • @ = Indicator that row and column information follows.
                  • rr = Row number (01-02) on the display.
                  • cc = Column number (01-40) on the display.
                The following example activates tones for an invalid transaction and writes record 3 in File 4 to the display:
                • C1$403
              Note:
              CMD C is processed only when the terminal is waiting for an interactive response (when DCT is waiting for a response in interactive mode to acknowledge receipt of a transaction record by the terminal controller.).

              CMD D&mdash.Initiate Data Collection from Terminal Controller

              This command allows the terminal controller to initiate a data collection transaction program at the terminal. CMD D can have multiple key commands appended including all of the transaction program command set and the :6 command. CMD D allows command sequences that are longer than one communication packet. If the terminating record separator (RS) is not present in a CMD D, the continuation of the command is assumed to follow in the next CMD D. The command sequence is buffered (up to 255 bytes) until the RS is found in a following CMD D.

              The ability to send transaction programs up to 255-byte lengths is an enhancement of the 7525's function. This function is available in both the 7525 compatibility and enhanced modes.

              :6(text)

              (text) is the message to be displayed.

              The format for this command is:

                   => STX, addr, addr, D, key commands, RS, CS1, CS2, ETX
                   <= ACK or NAK
              In interactive or interactive/buffered mode, CMD D is accepted by the terminal, and CMD B, CMD C, or CMD 2 is used for completing a transaction. This provides the flexibility of using the terminal in a fully interactive mode, allowing the terminal controller to control each step in the data collection process.

              Transactions created with CMD D contain a function ID as follows:

              • Enhanced mode
                • BFC = buffered mode
                • IFC = interactive mode
              • 7525 Compatibility mode
                • 31 = buffered mode
                • 81 = interactive mode
              Example:
              D:010:11000:6Enter Dept:20500
              The preceding example generates a transaction from the terminal. A prompt is displayed (File 8 record 10) with a 10-character badge read expected. Next, ENTER DEPT is displayed with a five-character numeric input expected. The resulting transaction may be polled from the terminal.

              Notes:

              1. To prevent disturbance during normal transactions, CMD D is processed only during terminal idle times.
              2. Succeeding the CMD D command with a CMD 1 command, and inspecting bytes 8 and 9 of the response may be used to determine if the command CMD D was successfully processed.
              l.

              CMD E&mdash. Write DO Point

              This commands writes a value or toggles selected DO points for a specified duration.

              The format of this command is:

                   => STX, addr, addr, E, {text...}, RS,
                      CS1, CS2, ETX
                   <= ACK or NAK
              The text is a string of four ASCII characters, pvtt

              Where:

              • p = DO point 0-7 to write
              • v = Value to write:
                • 0 = Clear DO point
                • 1 = Set DO point
                • 2 = Toggle current state of the DO (change to the opposite state)
              • tt = Seconds from 00-99 to hold a toggled DO point in its new state. The value of 00 = infinity
              Note:
              If multiple DO points are specified in the command, they are executed sequentially.
              .

              CMD F&mdash.Storage Query

              This command determines the usable RAM remaining in the DCT.

              The format for this command is:

                   => STX, addr, addr, F, RS, CS1, CS2, ETX
                   <= STX, data, CS1, CS2, ETX
              The data is a string of 12 ASCII characters defining the RAM status of the DCT. The first 6 bytes give the number of bytes of RAM remaining in the DCT and the field is right-justified and padded on the left with ASCII zeroes. The remaining 6 bytes are reserved.

              CMD G&mdash.Execute Transaction Program in Simulated Mode

              This command allows execution of a transaction program already loaded into the 7526 DCT, and simulates the pressing of a key or other event which normally starts the desired transaction program.

              Once the event has been simulated with command CMD G, processing the event takes place in the same manner as if the real event had occurred and the transaction record(s) are created as defined by the transaction program.

              The format for this command is:

                   => STX, addr, addr, G, function ID, RS, CS1, CS2, ETX
                   <= ACK or NAK
              The function ID is a two byte hexadecimal-ASCII field that represents a hex value. The function ID fields are described in "File 9&mdash.Transaction Queue File".

              Notes:

              1. To prevent disturbance during normal transactions, CMD G execution is limited to terminal idle times.
              2. Following the CMD G with CMD 1 is useful in determining if the transaction program was started.
              l.

              CMD H&mdash.Vary Communications Turn-Around Time

              This command varies the terminal delay before transmitting. This allows optimizing the system response time if the host turn-around time is less than the default of 5 milliseconds or if the communications hardware has timing variances.

              The format for this command is:

                   => STX, addr, addr, H, text, RS, CS1, CS2, ETX
                   <= ACK or NAK
              The text portion consists of two ASCII numeric characters whose value can be from 01-99. This corresponds to milliseconds, and the new value replaces the previous or default value of 5 ms.

              CMD I&mdash.Set User Variable

              The format for this command is:
                   => STX, addr, addr, I, text, CS1, CS2, ETX
                   <= ACK or NAK
              The text is: nnnccc....cc

              Where:

              • nnn = user variable number (001-998)
              • ccc....cc = characters to set in user variable, 245 bytes maximum
              Note:
              With V1.02 or higher of the 7526 microcode, the number of user variables and the size of the user variables are configurable.
              .

              CMD IM&mdash.Set Multiple User Variables

              Note:
              This command is only available in Microcode 4.0 or above, and thus requires presence of the optional Ethernet-Serial-Parallel card.
              This command allows several terminal user variables to be set via a single host command. This greatly speeds the process due to the reduction in protocol packets involved.

              The format for this command is:

                   => STX, addr, addr, IM, text, CS1, CS2, ETX
                   <= ACK or NAK
              The text is: nnnlllccc....cc, RS, nnnlllccc....cc, RS, ...

              Where:

              • nnn = user variable number (001-999)
              • lll = length of data for the specified user variable
              • ccc....cc = character data to which the user variable should be set
              The nnnlllccc....cc, RS sequence can be repeated for as many variables need to be set. The variables are set in the order that they are presented in the command. The total length of a single IM command cannot exceed 472 bytes.

              This command will return NAK if any error occurs; there is no need to send CMD 1 to verify its success.

              Note:

              With V1.02 or higher of the 7526 microcode, the number of user variables and the size of the user variables are configurable.
              .

              CMD J9&mdash.Configuration Query

              This command returns the hardware and firmware configuration of the terminal.

              The format for this command is:

              => STX, addr, addr, J9, CS1, CS2, ETX
              <= STX, J9, version, display, mode, ramsize, coprocessor, pio, CS1, CS2,
              ETX
              Where:
              • version = ROM microcode major and minor versions; two binary bytes. (For example, 01.00 would return 0100.)
              • display = Display type; one binary byte. Valid display types:
                • 00 = Two-line display
                • 03 = One-line display
              • mode = Terminal operating mode; one binary byte
                • 10 = 7525 Compatibility mode
                • 11 = Enhanced mode
              • ramsize = Size of RAM in paragraphs&mdash.one binary word.
              • coprocessor = Installation status; one binary byte
                • 00 = Coprocessor not installed
                • 01 = Coprocessor installed
              • pio = Setting of the printer port/DI/DO port; one binary byte.
                • 00 = Printer.
                • 01 = DI/DO.
              Note:
              A paragraph is equal to 16 bytes.
              .

              CMD K&mdash.Transaction Release

              Command K is used to inform the 7526 that it may release the single referenced transaction from its non-volatile memory.

              The format for this command is:

                => STX, ADDR, ADDR, K, text, CS1, CS2, ETX
               
                <= ACK or NAK
              Where:
              • text is the transaction sequence number (00000-00099)
              • Even though the 7526 sequence number is currently only 2 bytes in length, this command uses 5 bytes. Therefore the first 3 bytes will always be zeros.

                The text may also be 'XXXXX' to tell the terminal to release the first transaction in its queue regardless of its sequence number.

              This command is only available when the terminal is communicating via the Ethernet port.

              CMD L&mdash.Communications Loop-Back

              Note:
              This command is valid only for Microcode 4.0 or above.
              Command L is used to test the communications link to a 7526.

              The format for this command is:

                => STX, ADDR, ADDR, L, text, CS1, CS2, ETX
               
                <= STX, L, text, CS1, CS2, ETX
              Where:
              • text refers to any ASCII data string, 121 bytes maximum.

              CMD Mx&mdash.Custom Function Routine Control

              The Mx commands are used to load, start and control Custom Function Routines (CFRs):
              • CMD MA&mdash.Request CFR Status
              • CMD MB&mdash.Allocate Space for CFR
              • CMD MC&mdash.Load CFR Image
              • CMD MD&mdash.Start CFR.
              Note:
              Refer to Chapter 9. "Writing Custom Function Routines" for details on using the CFR commands.
              .

              CMD MA&mdash.Request CFR Status

              This command requests the CFR loaded and enabled status.

              The format for this command is:

                   => STX, addr, addr, MA, CS1, CS2, ETX
                   <= STX, status, size, CS1, CS2, ETX
              The status is a single binary byte as follows: 00 = No CFR loaded 01 = CFR in process of being loaded 02 = CFR enabled The size is one binary word and is in paragraphs. A zero size is returned if no space is allocated for a CFR.

              Note:

              A paragraph is equal to 16 bytes.

              CMD MB&mdash.Allocate Space for CFR

              This command allocates space to load a CFR and returns a starting address in paragraphs.

              The format for this command is:

                   => STX, addr, addr, MB, size, CS1, CS2, ETX
                   <= STX, paragraph, CS1, CS2, ETX
              The size is two bytes (binary) and is in paragraphs. The maximum size is determined by memory availability.

              The base paragraph address is returned (2 bytes, binary) to the controller. A base address of 0 is returned if there is insufficient memory. If a CFR is already loaded, this command disables it and initiates a new CFR load sequence.

              Notes:

              1. The terminal must be out of service prior to execution of this command.
              2. The size and paragraph parameters may correspond to control characters that must be encoded (see "Control Characters").
              3. The initial size cannot be exceeded without resetting the terminal.
              l.

              CMD MC&mdash.Load CFR Image

              This command loads the CFR executable image.

              The format for this command is:

                   => STX, addr, addr, MC, number, data, CS1, CS2, ETX
                   <= ACK or NAK
              The number (2 binary bytes, starting at zero) is a block counter to ensure that no data is lost or repeated.

              The data is the CFR image, and may be transmitted in packets with a maximum length, including the control and transparency characters, of:

              • 255 characters for RS-485 asynchronous host/server connection
              • 512 characters for TCP/IP Ethernet host/server connection
              Notes:
              1. A NAK is returned by the DCT if the number is incorrect.
              2. The terminal must be out of service prior to executing this command.
              3. Control character encoding may be required (see "Control Characters"). l.
              4. CMD MD&mdash.Start CFR

                This command notifies the terminal to initialize the CFR.

                The format for this command is:

                     => STX, addr, addr, MD, number, CS1, CS2, ETX
                     <= ACK or NAK
                The number (2 binary bytes) is the block counter as in CMD MC and must be one greater than the last number used in a CMD MC.

                Notes:

                1. A NAK is returned if the number is incorrect or a CMD MB and CMD MC have not been executed.
                2. The terminal must be out of service prior to executing this command.
                3. Control character encoding may be required (see "Control Characters"). l.
                4. CMD P&mdash.Set Terminal Mode

                  This command sets the terminal mode to either 7525 compatibility or enhanced mode.

                  The format for this command is:

                       => STX, addr addr, P, mode, RS, CS1, CS2, ETX
                       <= ACK or NAK
                  Where:
                  • mode = Terminal operating mode, ASCII character
                    • 0 = 7525 compatibility
                    • 1 = enhanced
                  Note:
                  When File 0 is configured properly and loaded after executing CMD P, it overrides or changes the operating mode as set by CMD P. However, if CMD P is issued after completing a download of the 7526, it will override the effects of File 0 Record 00 Offset 203.
                  .

                  CMD Q&mdash.Read User Variable

                  The format for this command is:
                       => STX, addr, addr, Q, text, RS, CS1, CS2, ETX
                       <= STX, Q, data, CS1, CS2, ETX
                  The text is:
                  • nnn = user variable number (000-998)
                  Where:
                  • data = characters read from the user variable, 251 bytes maximum
                  Notes:
                  1. The end of the data is determined by the length of data sent. There may be nulls (00h) or other special characters in the data that is returned. If the user variable was not set or cleared before being accessed, the effects are indeterminate, but may include a reset of the system.
                  2. This feature is available in V1.02 and above. l.
                  3. CMD R&mdash.Read Terminal Memory

                    This command allows reading the terminal RAM for program debugging and diagnostic purposes.

                    The format for this command is:

                         => STX, addr addr, R, paragraph, CS1, CS2, ETX
                         <= STX, data, CS1, CS2, ETX
                    Where:
                    • paragraph = Two byte (binary) address from which 64 consecutive bytes will be read
                    • data = 64 bytes of binary data starting at the paragraph address
                    Notes:
                    1. If non-existent memory is addressed, undefined data is returned.
                    2. This command returns up to 196 bytes of data, depending on any control character encoding that may be required (see "Control Characters"). l.
                    3. CMD V&mdash.Positive or Negative Response to Remote Validation

                      This command provides a positive or negative response to remote validation requests from the terminal.

                      The format for this command is:

                           => STX, addr addr, V, text, RS, CS1, CS2, ETX
                           <= ACK or NAK
                      The text is a string of five or eight ASCII characters, ssffr

                      Where:

                      • ss = the sequence number of the transaction that requested the remote validation in decimal (00&mdash.99). The sequence number may also be 5 digits long, which would range from (00000&mdash.99999). In this case the field number would be in bytes 6 and 7, and the response would be in byte 8.
                      • ff = the field number in decimal (01&mdash.99), or 00 to indicate that the field information is not used.
                      • r = response to the remote validation
                        • ASCII P = positive response (the data was found to be valid)
                        • ASCII N = negative response (the data was found to be invalid)
                      Note:
                      This feature is available in V2.00 and above.

                      Chapter 7. Power-Up and Download Specifications

                      This chapter discusses the states which a 7526 DCT may be in as the result of a power-up, and specifies the download sequences for the 7526 DCT and parameter files.