MagTek TTL - Manual (Page 22)

I/O Interface for TTL Magnetic Stripe Readers
18
INSERTION READERS
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 be designed to emphasize data capture
during the card withdrawal stroke.
For the most reliable operation:
1.
Read the card upon insertion. When the card hits the backstop (Card Present will go
high), check the data for errors.
2.
If the data contains no errors, output that data, start sentinel first, after the card has been
withdrawn.
3.
If an error was detected, clear that data and get ready to read the card again upon
withdrawal.
4.
After the card is removed (Card Present will go high), check the data for errors.
5.
If no errors are found, output that data, start sentinel first.
6.
If an error is detected, indicate to the host that an error was detected, indicate to the
customer to insert the card again.