MagTek TTL - Manual (Page 14)

I/O Interface for TTL Magnetic Stripe Readers
10
TIMING
The timing for Card Present, Strobe, and Data is as shown in Figure 2-3.
CARD PRESENT
DATA
STROBE
1 1 1 0 0 0 0 0 1 1 0 0 0 0 0
Bit
Time
STROBE WIDTH APPROXIMATELY
25-50% OF BIT TIME
Notes:
1. Time out of the CARD PRESENT signal occurs approximately 150 ms after the last strobe transition.
2. DATA is valid 1.0
μ sec before the negative edge of STROBE.
Figure 2-3. Timing
DATA
The Data signal is valid while the strobe is low. If the Data signal is high, the bit is a zero. If the
Data signal is low, the bit is a one.
STROBE
The Strobe signal indicates when Data is valid. It is recommended that Data be loaded by the
user with the leading edge (negative) of the Strobe.
CARD PRESENT
Card Present will go low after 14/15 flux reversals from the head. Card Present will return high
150 milliseconds after the last flux reversal.