MagTek IntelliStripe 60 99875135 - Manual (Page 21)

Section 2. Installation
13
SENSING SWITCHES
The sensing switches provide outputs to the 26-pin I/O connector and are routed as follows:
Pin 9 = Card Present Switch
Pin 10 = Card Seated Switch
Pin 18 = Card Latched Switch
The switch outputs are isolated from other circuits by the switch. An external interface pull-up
resistor of 10K ohms, supplied by the Host interface, ensures proper sensing operation over the
specified environmental range. The resistors should be connected to pins 9, 10, and 18.
Card Present Switch
A snap-action switch operates by the spring-loaded card guide at the entrance of the Reader. The
switch is actuated when the card is inserted into the card slot. The signal at the interface I/O
connector is normally open and is grounded when the card is inserted into the Reader.
Card Seated Switch
A snap-action switch is operated when a card is fully inserted into the Reader (card is at the fully
rearward position). The signal at the interface I/O connector is normally open and is grounded
when the card is inserted into the Reader.
On insertion of the card, there may be some spurious transitions (mechanical switch bounce) at
the Card Seated output, which do not exceed 4 ms. These transitions occur before the ICC chip
contacts stabilize (stable contact with ICC pads) within a maximum of 40 ms from the stable
state of the Card Seated output.
The first transition from the Card Seated output on withdrawal of the card is guaranteed to occur
1 ms before the ICC contacts lift. During the period between the two events, the contact
resistance can increase to (but not exceed) 100 ohms for C1, C5, and C8 contacts, and 500 ohms
for C2, C3, C4, and C8 contacts. For C7 the limit is 700 ohms.
Subsequent to the first transition from the Card Seated sensor, there can be additional transitions
because of the mechanical bounce of the Card Seated switch contacts.
Card Latch Switch
A snap-action switch is operated by the latch mechanism. The signal at the interface I/O
connector is open when the latch is disengaged and is grounded when the latch is engaged.
Latch Control
The latch is controlled by the Latch Control signal (pin 12). The latch is engaged when the
Latch Control signal transitions from ground to Vcc. The latch is disengaged when the Latch
Control signal transitions from Vcc to ground. It takes about 40ms for the latch to completely
engage or disengage.