MAINTENANCE AND LUBRICA TION 269

This a - unswitched battery power can used power external devices that require power all even when the key turned This source protected a - amp circuit breaker

Ignition Post (IGN)

This a - switched battery power can used power external devices that require power only when the key turned This source protected a - amp circuit breaker

Ground Post (GND)

This a ground connection. can used a power return connection for external devices.

W Arning

The tachometer output, speedometer output, and serial links A and B e for specific hookups. These terminals should used only for their specified purposes and connection these terminals should done only a qualified service technician.

Note: The tachometer output and speedometer output are 50% duty cycle, T ransistor - T ransistor Logic (TTL) square wave signals that are calibrated provide a standard pulse rate pulses per engine revolution for the tachometer output and pulses per mile for the speedometer TTL compatibility these outputs may fected other devices connected these outputs.

T achometer (RPM) Output

This terminal used for devices requiring information for engine speed (See the W arning and Note

Speedometer (MPH) Output

This terminal used for devices requiring information for vehicle speed signals. (See the W arning and Note above.)

SAE/A T A J1708 Posts (Serial Links A and