Mack CSM 2010 - Page 226

218MAINTENANCEANDLUBRICATION
Tachometer(RPM)Output
Thisterminalistobeusedfordevicesrequiringinformationforenginespeedsignals.(See
theWarningandNoteabove.)
WARNING
Thetachometeroutput,speedometer
output,andseriallinksAandBarefor
specichookups.Theseterminalsshould
beusedonlyfortheirspeciedpurposes
andconnectiontotheseterminalsshouldbe
doneonlybyaqualiedservicetechnician.
Note:Thetachometeroutputand
speedometeroutputare50%dutycycle,
Transistor-TransistorLogic(TTL)
compatible,squarewavesignalsthatare
calibratedtoprovideastandardpulserate
of12pulsesperenginerevolutionforthe
tachometeroutputand18,645pulsesper
kilometerforthespeedometeroutput.TTL
compatibilityoftheseoutputsmaybeaffected
byotherdevicesconnectedtotheseoutputs.
Speedometer(KPH)Output
Thisterminalistobeusedfordevicesrequiringinformationforvehiclespeedsignals.
(SeetheWarningandNotebelow).
SAE/ATAJ1708Posts(SerialLinksAandB)
Thisisaserialcommunicationinterface.ItconformstotheSAE/ATAJ1708Recommended
PracticeforSerialDataCommunicationsBetweenMicrocomputerSystemsinHeavy-Duty
VehicleApplications.(SeetheWarningabove.)