Section 3. Commands, Formats, and Timing
INTERFACE WIRE LIST FOR MT-215232
The interface wire list describes the unit with and without control signals in the buffered and unbuffered
modes, D9 and D25 connectors, and LED connections.
Control Signals
The control signals are defined as: DSR, pin 5; DTR, pin 7; CTS, pin 9; RTS, pin 11.
Without control signals in the unbuffered mode, the card reader will transmit the data immediately upon
removal of the card.
Without control signals in the buffered mode, the card reader will transmit the data upon removal of the
card and immediately after the Host has polled the card reader.
With control signals connected in the unbuffered mode, the unit will signal the Host (RTS goes positive)
when it has a message and wait for the Host to signal that it is ready to accept the data. The Host raises
CTS to a positive level to receive the data, and RTS will return to negative after data has been
transmitted.
With control signals connected in the buffered mode, after the card is removed and polled by the Host,
and the Host signals that it is ready to accept data, the data will be transmitted.
Note
Normally this last configuration is not used if the Host has full command of
the control signals
Power and Connector Mating
The +5 VDC ± 5% at 0.045 Amps power can be obtained from an external power supply or from the Host
(not available on the "D" COM port connector).
The reader mates to a 20 pin connector (P2), and the Host has a "D type" connector (P3) which is
normally designated as Com 1 or Com 2.
Part numbers for the 3M interface: Connector 3421-6000; Flat gray cable 3365-20; or Flat multi-color
cable: 3302-20.
Tables 3-2 through 3-5 describe the correct wiring schemes for 25- and 9-pin “D’’ connectors with and
without control signals.
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