Mark E. Skeels wrote:
> Can you guys think of any way a phone line could be induced to go off 
> hook via a stimulus external to the phone line (not electrically connected?
> 
> Mark

This happens at my daughters home occasionally.  She has a CAT-3 system; 
her 3 cats chase each other around the house and sometimes knock the 
phone handset out of the cradle causing it to go off hook.  Absolutely 
no electrical connection from the cats to the phone line.

More seriously, "off hook" means that the two wires that comprise your 
phone line have been connected together.  This makes the system go from 
no (or very low) current to something in the range of 20mA, give or take 
the various tolerances of the system.  So to go off hook, you must do 
something to cause current to flow through your phone line.
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