[GreenKeys] Teletype (telephone) Local Loops

[Roy Morgan]

Paul,

Especially considering your experience with *real* telephone and teletype circuits, may I recommend:

“The Green Book”
Tu Wit:
Principles of Electricity
   applied to
Telephone and Telegraph Work

The copy I have here is entitled on the tile page:

A Training Course Text
Prepared for Employees of the
Long Lines Department
AMERICAN TELEPHONE AND TELEGRAPH COMPANY
November 1938
(Reprinted with corrections, January, 1941)

No teletype library should be without one.
There we’re a number of editions, the later ones omitted some material from the earlier ones I think.

I find one on Amazon ("1941 edition" - could be the 1941 reprint) but UNFORTUNATELY, the price is $68.00 !!!  The good news is that there is one other one offered for less that $10.  Better scoff it up quick!!

I would not be surprised to find it in  PDF form in one of the very deep collections of technical books online.  Can anyone post a link to that somewhere?

I, too will be grateful for the experience of others about this topic.  I have little experience with local loops, but I do have a couple  of polar relays and a Model 28 loop supply (here), and some M-15 equipment (in distant storage) that will eventually get assembled into a working setup.

Roy


> On May 25, 2020, at 11:39 AM, ad7i <ad7i at ad7i.net> wrote:
> 
> Sorry for the long-winded backgrounding before posing my question…
>  
> I was fortunate to start my career with "the phone company" when I was 16 in a small central office at an independent telephone company in Washington State. ...
>  
> ... my question ... has to do with DC teletype loops (up to 3 or 4 miles in length) over dry* pairs leased from the telephone company.   In the case of long DC loops for TTY service I assume that the current limiting was done via a large wattage resistor located in the same building as the voltage source (and not at the customers location).  Is that correct or usually correct?
... 
> I'd be grateful for whatever knowledge members have to share on the topic of DC signaling over telco lease dry pairs. 

Roy Morgan
K1LKY since 1958
k1lky68 at gmail.com