500 m

200 m

100 m

2000 m

500 m

200 m

100 m

700 m

simplex

four wire circuit

full duplex

half duplex

carrier signal

baseband signal

primary singal

None of these

inserting a ′0 ′ in user stream to differentiate it with a lag

inserting a ′0 ′ in lag stream to avoid ambiguity

appending a nibble to the lag sequence

appending a nibble to the use data stream