This unit can be used where an older type vehicle is to be fitted with a modern tachograph requiring two signal inputs. Signal 1 is the normal signal and Signal 2 is inverse of Signal 1.
Vehicles manufactured after 1998 with electronic speedo and requiring a tachograph to be installed should use an SL205 interface. This protects both the supply signal to the tachograph head and the input signal from the vehicile's electronic transducer.
The SMG1 is an economical interface where cost savings are required on older vehicles.
