Recently I made several RS-232 null modem cables, using a multiconductor
cable of 7 individual wires, a foil sheath around the wire bundle, and
with a bare stranded conductor spiraled around the foil. After talking
to several technicians, they all agreed that the bare outer conductor
should be included into the system ground pin (5) on one end.
No one knew if this practice holds true for all transmission rates and
cable lenghths that might be encountered, or which side the bare was to
be included in if the data flow would be two way, as opposed to one way
Are there circumstances where the outer bare conductor is connected to
both, or neither side's ground, and what effect does cable length or
transmission rate have on this?
Appreciate the feedback.
GE Industrial Control Systems
Ft. Wayne, IN