CSQ is an abbreviation for 'Carrier SQuelch'. It's another name for PL tones (which is technically Private Line Tone, which is the name Motorola gave it) or CTCSS. I think CSQ is the GE version of PL. I dunno, but I think they are similar in steps to PL, but I'll have to look into it more.
"Silent enim leges inter arma." -- Cicero