The tachograph programmer CD400 supports
the TSU 2.0 1391

TSU 2.0 1391 direct successor to the TSU 1.0

Unlike its predecessor, the TSU 2.0 triggers a safety mechanism upon activation that locks critical parameters against subsequent changes.
Activation can be performed manually after calibration or happens automatically once the vehicle's mileage exceeds 1000 km. 
To modify parameters after this lock is active, authorized users must bypass it using the "Key on the server" procedure.

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