MagTek MT-215 TTL HALF CARD - Manual (Page 13)

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SECTION 3. OPERATION
The orientation of card insertion is shown in Figure 2-2. The timing for Back Sensor and Card Present is shown
in Figure 3-1.
TIMING FOR BACK SENSOR AND CARD PRESENT
Figure 3-1 shows the timing for the Back Sensor and the Card Present signals.
HEAD OUTPUT
SIGNAL
TIME OF INSERTION TIME OF WITHDRAWAL
CARD PRESENT
AT CONNECTOR
INTERNAL CARD
PRESENT
BACK SENSOR
AT CONNECTOR
ACTIVE DATA
MOST RELIABLE
ACTIVE DATA
NOTE 1 NOTE 1
NOTE 1
NOT TO SCALE NOTE 1:
Time out of the internal card present signal occurs approximately 150 ms
after the last strobe transition. The internal card present signal becomes
active when the movement of an encoded magnetic stripe past the read
head generates a signal. The back sensor and internal card present are
gated together to reduce the dwell time needed before the read-on-
withdrawal can be initiated.
Figure 3-1. Timing for Back Sensor and Card Present Signals
While it is possible for the Card Reader to read data on either the insertion or withdrawal stroke, it should be
noted that card reading is most reliable during the card withdrawal stroke. For this reason MagTek recommends
that customer’s software should be designed to emphasize data capture during the card withdrawal stroke. For
the most reliable operation: Read the card upon insertion, when the card present goes high, check for errors, if
no errors, output the data, start sentinel first, after the card is withdrawn. If an error is detected, clear the stored
data and read the card on withdrawal, if no errors, output the data, start sentinel first, otherwise output an error
indication or a try again message.
For further information about magnetic stripe readers, refer to MagTek part number 99875148, I/O Interface for
TTL Magnetic Stripe Readers, Technical Reference Manual.