VeriFone MX800 Series - Page 53

DEVICE DRIVERS
SetSecurePINDisplayParameters()
M
X
800 SERIES PROGRAMMERS GUIDE 53
With the callback function, the PIN entry process can control the audio and visual
aspects as each key press is detected, and its prototype is:
void callback(char value);
Example 1: when a valid numeric entry is detected, the function will be called
once:
callback(0x71); /* Tell the application to play normal sound and to
display <echo> character */
Example 2: when the backspace key is detected:
callback(0x72); /* Tell the application to play normal sound and that
BACKSPACE was pressed*/
Example 3: when a key is pressed to clear the line when 3 inputs are entered:
callback(0x73); /* Tell the application to play normal sound and that
CLEAR was pressed*/
Table 6
Value Action
Lower nibble:
0x?1 A numeric key was pressed. A PIN digit has been added to the
internal PIN buffer. Application should display an <echo>
character.
0x?2 BACKSPACE key was pressed. A PIN digit has been removed
from the internal PIN buffer. Application should display a
<default> character (e.g. space, ‘-‘ or ‘_’) in place of the last
<echo> character.
0x?3 CLEAR key was pressed. All PIN digits have been removed from
the internal PIN buffer. Application should replace all <echo>
characters with <default> characters.
0x?5 Other key #1 was pressed. Pin Entry will be aborted as if the
CANCEL key was pressed. The application can use this code to
define an option key such as a CREDIT button.
0x?6 Other key #2 was pressed. Pin Entry will be aborted as if the
CANCEL key was pressed. The application can use this code to
define an option key such as a CREDIT button.
Upper nibble:
0x7? Play “normal“ sound
0xF? Play "error" sound. This is sent when:
• BACKSPACE or CLEAR is pressed when there is no PIN digit
in the internal buffer.
• A numeric key is pressed when there is already the maximum
number of PIN digits in the internal buffer.
• ENTER is pressed when there is not the minimum number of
PIN digits in the internal buffer.