[GreenKeys] RE: What is a polar relay for?

[Roy Morgan]

On Dec 31, 2008, at 12:05 AM, amourdutigre wrote:

> I just ordered this book from an Amazon book dealer, cost less than  
> the shipping for standard delivery at $3.99.
... "Principles of Electricity applied to Telephone and Telegraph  
Work" put out by AT&T

This is "the Green Book" and tells a LOT about telephone and  
telegraphs. They sometimes cost much more than $4.  I have a couple  
different editions, and there are some differences.

Roy

Roy Morgan
k1lky at earthlink.net
529 Cobb St.
Groton NY, 13073