check now
In the DB-9 connector backshell is are a 4.7K resistor and a 47k resistor. The shield of the coax connects to pin 5 of the DB-9. The center conductor of the coax connects to pin 2 of the DB-9. The 4.7K connects between pins 2 and 3 of the DB-9. The 47k connects from pin 3 to pin 5 of the DB-9. This is a standard serial connector pinout where pin 2 transmits data to the PC, pin 3 receives data from the PC and pin 5 is ground.
The other end of the cable is a circuit board about .4" wide by .9" long. The coax cable comes into one end of the board and the 4 pin programming connector hangs off the other end of the board.
-------------------------------------------------- -------------
| | |
| L4P Y2 4 3 C685 | |
| 7 3 | OSC1 |
| K 1 | |
| | |
| D3 | |
coax | D3 | OSC2 |
=========|====== SX20AC/SS | |
| 331 50.00 | |
| | VDD |
| | |
| ____ | |
| / 22 \ 489 | VSS |
| ( 0G ) A106 | |
| \____/ | |
------------------------------------------------- -------------
| Marking | Package | Description | Usage |
|---|---|---|---|
| L4P | SOT-23 | ??? | ??? |
| Y2 | SOT-23 | BZX84C12, 12 volt zener | 12 volt supply regulator |
| 47K | 805 | 47K resistor | ??? |
| 331 | 805 | 330 ohm resistor | ??? |
| D3 | 6 pin | diode array? | ??? |
| 331 | 805 | 330 ohm resistor | ??? |
| 220G | coil | 22uh coil? | +12 volt supply |
| 489 | SOT-23 | FMMT489, NPN, 1 amp | ??? |
| SX20AC/SS | SSO | Scenix micro | Command, Control, Communications |
| C685 | 1206 | 6.85uF cap | +12 volt supply filter |
| D3 | 6 pin | diode array? | ??? |
| 50.00 | 3 contact | Ceramic resonator | 50MHz oscillator |
| A106 | 1206 | 10uF cap | Power supply bypass |
The SX-Key applies the +12 volts to the OSC1 of the SX for both reading and writing.
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Last updated April 20, 1998
Copyright 1998 Richard Ottosen