QUESTION:
How does the information transfer from Pathfinder to the control room and
then pass through to the internet?

ANSWER from David Mittman on November 17, 1997:
Under normal circumstances, the Sagan Memorial Station transmits its data
over a 13-watt signal from an 11-inch diameter antenna pointed at Earth.
That signal is received using either 70-meter or 34-meter ground stations on
Earth. (The ground stations are located in California, Australia or Spain.)
The signal is analyzed and its data portion is stripped off, reformatted,
and sent to the Jet Propulsion Laboratory (JPL) in California. Once received
at JPL, the data is stored to optical disk, and sent off to various
computers for further storage and analysis. Scientists present at the time
this data is being received can view images reconstructed from individual
data packets. Engineering data describing the health of the spacecraft is
also immediately available to the spacecraft flight team.

The data which appear on the Mars Pathfinder web site has been selected by
the Project Scientist for distribution, and is usually transfered to the web
site without additional processing. Large panoramas made up of multiple
frames are processed to form a relatively seamless image.