Question

How much data can a digital wave send. (The maximum data)

Answer 1

... A digital signal sent over a telephone connection is
limited to about 60,000 bits (7,500 Bytes) per second. 

... Data sent over "Category 5" and "Category 6" Ethernet cables
usually runs at either 100 megabits or 1 gigabit per second. 

... Data sent over wideband microwave radio signals
is currently capable of up to 1 gigabit (1000 megabits)
per second.

... Fiber optic systems typically operate at 10 gigabits or
40 gigabits per second, but much higher rates have been
accomplished.

In 2010, Nippon Telegraph and Telephone Corporation (of Japan)
transferred 69,100 gigabits per second (69.1 Terabits) over a single
fiber that was about 150 miles long.

In 2012, the same company transferred 1 million gigabits per second
(1 petabit) over a single fiber about 31 miles long.
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1 megabit  =  1 million bits

1 gigabit = 1 billion bits = 1,000 megabits

1 Terabit = 1,000 gigabits = 1 million megabits

1 petabit = 1,000 Terabits = 1 million gigabits = 1 billion megabits

               = 1 billion million bits .