12V (external power supply) < - > B+ of the ECU as well as the AVDI (pin 17 of the DB25 or pin 16 of the CB100 OBD cable)

12V (external power supply) < - > key switch < - > IGN of the ECU (a key switch should be connected between 12V power supply and IGN pin of the ECU)

GND (external power supply) < - > GND of the ECU and GND as well as the AVDI(pin 5 of the DB25< - male> or pin 6 of the CB100 OBD cable).

K-Line of the AVDI (PIN 7) < - > K-Line of the ECU(also called Data signal cable)

A key switch (sometimes called a lock switch) is a key-operated switch. Key switches are used in situations where access needs to be restricted to the switch’s functions.