Newbie - Translation rules syntax

Hi All.

I just love Cisco right now. I'm a newbie to IPT telephony and I have successfully configured outgoing calls on a UC500, allthough I don't understand mutch of the translation rule syntax. Can anyone pinpoint me to some resource or something that explains the meaning of all the signs, dots, slashes, dollarsigns, parentheses in the rule statements like these?

rule 1 /246085200/ /15/
rule 2 /^91900......./ //
rule 3 /^9\(..........\)$/ /1\1/
rule 4 /^9\(.......\)$/ /1619\1/

They don't mean much to me right now allthough I understand that they are there to translate phonenumbers.

Thanx