MagTek MT-215 TTL HALF CARD - Manual (Page 14)

MT-215 TTL Half Card Reader
8
TIMING FOR DATA AND STROBE
The timing for Data and Strobe is shown in Figure 3-2.
0 0 0 0 1 1 1 1 0 0 1 1 1
DATA
STROBE
BACK SENSOR
SW1
NOTE 4
CARD PRESENT
NOTE 5
NOTE 3
BIT
TIME
STROBE WIDTH
APPROXIMATELY
25-50% OF BIT TIME
Notes
1.
The CARD PRESENT signal is low when a recorded card is being moved across the read head. The rear
sensor switch is connected with CARD PRESENT to insure that CARD PRESENT will go high when the
card is fully inserted. Time-out of the CARD PRESENT signal occurs approximately 150ms after the last
strobe transition, after card removal.
The output of the rear sensor is quiescently high. It goes low when the card is completely inserted and
remains that way as long as the card is completely inserted (Pin 3 on the single track, and Pin 5 on the d
track). ual
4. Switch 1 (SW1) is normally open. It closes after the first 0.85 inch of card is inserted and before the card
reaches the head gap. It will remain closed until all but 0.85 inch of the card has been removed. This
switch may be used for power saving for battery operation.
5. This is the time the card is against the back sensor.
6.
See MagTek P/N 99875148 for interfacing information.
Figure 3-2. Timing for Data and Strobe
2.
DATA is valid 1.0 μs (minimum) before the negative edge of STROBE.
3.
There are 8 or 9 head flux reversals for this configuration. These will be delayed (not output) before
enabling the Bit Recovery system.