�1���� Scope
�2����
Interchange equivalent circuit
�3����
Load
�4����
Generator
�5����
Significant levels (V1)
�6����
Signal characteristics
�7����
Detection of generator power-off or circuit failure
Annex� A � Operation from 20
kbit/s to 64 kbit/s
������� A.1���� Option 1
������� A.2���� Option 2