LINK TO CALEA STANDARDS DOCUMENT (Score 1)

Become informed; read the CALEA standard (TIA/EIA- J-STD-025):

http://216.239.35.100/search?q=cache:EOI2S1LqKLg C: ftp.tiaonline.org/TR-45/TR452/Incoming/EIA-J-STD-0 25.pdf+J-STD-025+pdf&hl=en

Let's not forget that modem singalling is also able to be intercepted.