MagTek SWIPE READERS WITH RS-232 - Manual (Page 21)

Properties and Commands
15
Sentinel Definitions
The start and end sentinels values can individually be specified by commands. The default
settings are shown in the Table 4-4.
Note
Changing the value of any of the sentinels does not actually
change the encoded value on the magnetic track; it merely
represents the sentinel in a unique way to help distinguish
differently formatted tracks.
Table 4-4. Start and End Sentinels
Value
Name Default
(hex)
Default
(ASCII)
Definition
S1 25 % Start Sentinel ISO/ABA Track 1
S2 3B ; Start Sentinel ISO/ABA Track 2
S3 2B + Start Sentinel ISO/ABA Track 3
S4 40 @ SS Non-standard (7bits) Track 2
S5 26 & SS Non-standard (7bits) Track 3
S6 23 # SS AAMVA track 3
SE 3F ? End Sentinel for all tracks all type
As with the switch settings, the sentinel parameters can be discovered by sending the
corresponding command for that value immediately followed by a CR. For instance, in order to
determine the present setting of the 7-bit track 3 start sentinel, send the following command:
<ESC>S5<CR>
The Reader will respond with the value, in nibbles:
<ACK><ESC>S526<CR>
Any ASCII character from 0x00 to 0x7F can be used as a sentinel. To change the value of the 7-
bit track 3 start sentinel to “!” (0x21), send the following command:
<ESC>S521<CR>
Again, as with the switch commands described above, send the Upload (UP) command followed
by the Reset (RS) command to complete the transaction.