The terminal database file (if present) associates each key code in the preceding tables with the hardware sequence that the key sends. Control keys (described in the table only as Control plus another key) are not defined in the terminal database file; they are directly mapped by the runtime system to the corresponding control-key ASCII value.
Control keys can be referred to in a KEYSTROKE entry by either their ASCII value or by the key code listed. The DEL key does not have a key code; it can be referred to only by its ASCII value (127).
Some keys may have more than one name. When this occurs, the names have the following precedence:
Here's one example: The left arrow key is associated in the terminal database file with the key code kl (line 14 of the table). On some terminals, the left arrow key sends the sequence ^H (Control-H), which makes it, implicitly, a "Control key" (line 3 of the table). So its second "name" is ^H. If, at the operating system level, ^H is assigned to the destructive Backspace function, it also has the key code ZB associated with it (line 1 of the table). Because the Host name takes precedence, the left arrow key acts as a destructive backspace.
If the host's backspace were redefined (by operating system command) to be some other key, then the left arrow key would be considered a "Left Arrow" key (kl).
It would be considered a Control-H (^H) only if the host's backspace were redefined as above and the terminal database file were edited to change or remove the "kl" definition.
See the Special Keys section for more details.