[GreenKeys] Why and When 7.00 vs. 7.42 unit code?

[Roy Morgan]

On Mar 12, 2014, at 10:56 PM, Jim Haynes <jhhaynes at earthlink.net> wrote:

> Something that is out there on the net is a scan of the AT&T Long Lines book "Principles of Electricity Applied to Telephone and Telegraph Work” … 1953 edition at:
> long-lines.net/sources/att_principles_ocr.pdf‎

This is the much-respected “Green Book” since the covers were green.

At the risk of starting a mad dash to collect them all, each edition differs from the earlier one in some ways.  The differences may be important or not depending on your interests.  In any case, any of them make very good bed time reading.

Roy

Roy Morgan
RoyMorgan at alum.mit.edu
K1LKY Since 1958