Understanding Automotive Electronics 8th Chapter 9

Communicationwithvehicles(whilemoving)beganwiththeintroductionofAMradioreceiversinthe1930s.Inthissamegeneralera,two-wayradiocommunicationviaradiowasusedbylawenforcementagencies.Theevolutionofciviliantwo-wayradiocommunicationsadvancedrelativelyslowlyuntiltheintroductionofcellularphones.