Autel scanners will only communicate with ECMs of vehicles with OBD II certification which typically , (at least in the USA) were 1996 and up and most makes sold in the USA required the familiar 16 pin OBDII connectors, basically just for generic OBDII monitor checks and testing , however some makes of cars continued to use the old style proprietary obd1 connectors for several years for more in depth bi directional testing of the engine control systems and access to access  other systems of the vehicle, until most manufactures access all module now on the single 16 pin OBD II connector.
  Some OBD 1 GM and Ford Vehicles in 94 and 95  had 16pin OBDII style connectors that , at least with Fords you might actually  be able to access a few  of the other systems (other than ECM) if you were to ID and scan the vehicle as a 96 model