7526 DCT Reference


ASCII Characters

The following table describes the ASCII characters and hexadecimal equivalents of the communication control characters discussed in this document.

Table 2. ASCII/Hex Cross-reference

+=======+=======+============================================================+
| ASCII |  Hex  |                        Description                         |
+=======+=======+============================================================+
|  SOH  |  01   |                      Start of header                       |
+-------+-------+------------------------------------------------------------+
|  STX  |  02   |                       Start of text                        |
+-------+-------+------------------------------------------------------------+
|  ETX  |  03   |                        End of text                         |
+-------+-------+------------------------------------------------------------+
|  ACK  |  06   |                  Positive acknowledgement                  |
+-------+-------+------------------------------------------------------------+
|  DC1  |  11   |                      Device control 1                      |
+-------+-------+------------------------------------------------------------+
|  DC2  |  12   |                      Device control 2                      |
+-------+-------+------------------------------------------------------------+
|  NAK  |  15   |                  Negative acknowledgement                  |
+-------+-------+------------------------------------------------------------+
|  CAN  |  18   |                           Cancel                           |
+-------+-------+------------------------------------------------------------+
|  ESC  |  1B   |                      Escape sequence                       |
+-------+-------+------------------------------------------------------------+
|  RS   |  1E   |                      Record separator                      |
+-------+-------+------------------------------------------------------------+
The following legends and symbols are used when describing the communications control commands.

Table 3. Communication Legends and Symbols

+===============+============================================================+
| Legend/Symbol |                        Description                         |
+===============+============================================================+
|      =>       |     Transmission from terminal controller to terminal      |
+---------------+------------------------------------------------------------+
|        <=        |     Transmission from terminal to terminal controller      |
+---------------+------------------------------------------------------------+
|     addr      |  Terminal address (lower case ASCII a-y and 0-6 or z for   |
|               |        broadcast). Provides 32 terminal addresses.         |
+---------------+------------------------------------------------------------+
|      CMD      |           Command ID character sent to terminal            |
+---------------+------------------------------------------------------------+
|   CS1, CS2    |                    Checksum characters                     |
+---------------+------------------------------------------------------------+
|     data      |  ASCII characters sent to the terminal controller from a   |
|               |         terminal as a result of a poll or command          |
+---------------+------------------------------------------------------------+
|     text      |  Parameters and data associated with a command sent to a   |
|               |           terminal from the terminal controller            |
+---------------+------------------------------------------------------------+
|      RS       |                      Record separator                      |
+---------------+------------------------------------------------------------+
|       f       |                      File identifier                       |
+---------------+------------------------------------------------------------+
(Ref #2.)