Determining date of manufacture for central air

[Chesnick]

Does anyone know of an internet resource that I can refer to that will give me information on how to determine the age of various brands of central air conditioners? I have found some information that takes me into the 1970's - 80's but nothing more recent.

Also where do I find out the brand names manufactured by each manufacturer?

Thanks

[mgbinspect]

In a most cases the year of manufacture is incorporated in the serial number if not plainly printed on the information plate of the condensing unit.