Detecting The Peripheral; Figure E-2 Stylistic 1200 Pen Tablet Dc Contact Dimensions - Fujitsu Stylistic 2300 Technical Reference Manual

Figure E-2 Stylistic 1200 Pen Tablet DC Contact Dimensions

Detecting the Peripheral

Since the 16-volt DC power input and 5-volt DC output positions are relatively close to each other, a
potential over-voltage hazard exists (i.e. 16 volts could be inadvertently applied to the 5-volt output if the
16-volt pin on a cradle device touches the 5-volt contact on the pen tablet) which could damage
peripherals connected to the high-usage contacts. So, peripherals which provide power to the pen tablet
should detect the presence of the pen tablet before turning on the 16-volt line. Also, consider
implementing over-voltage protection on the 5-volt line to protect peripherals connected to the 5-volt line
down stream.
The pen tablet detects the presence of a peripheral device connected to the high-usage contacts when
position 2 (the Detect signal) is grounded by the peripheral. Unfortunately, the pen tablet does not
provide such a detect signal to allow the peripheral to detect the presence of the pen tablet, so the
peripheral must detect the presence of the pen tablet by some other means.
One way for a peripheral to detect the pen tablet (and confirm that it is properly connected) is to monitor
position 4 for the presence of either +5 volts DC (pen tablet on) or zero volts (pen tablet off or suspended).
When either of these conditions exist, the 16-volt line can safely be turned on.
Note: Other methods (such as microswitches or other mechanical designs) could be used to detect the presence of
the pen tablet.
Detecting the Peripheral
Microsoft Corp. Exhibit 1020
E-3