[GreenKeys] East Wire and West Wire?

[dmm at lemur.com]

Might I trouble the list with a question about terminology?
It is probably (a) a FAQ, or (b) obvious to everyone except me,
or (c) completely unimportant, but I find it puzzling.
This probably comes from not having any practical experience
in the field (but doing it all from books, instead).

In reading teletype and telegraph books, I find that sometimes
lines are identified as the "east wire" the west wire.  What were the 
conventions for this?  Was it just arbitrary (another way of 
saying "A" and "B"), or was there a pattern/significance/meaning 
to East vs. West?

I've encountered this terminology in three places:

In TM 11-680 (Teletypewriter Circuits and Equipment (Fundamentals)),
and, more frequently, in TM 11-358 (Telegraph Central Office Set TC-3).
Here "East" and "West" seem to be just synonyms for "local" and "line."

In late 19th century textbooks such as Maver's _American Telegraphy
and Encyclopedia of the Telegraph_ (various editions, many of which
are online on Google Books).  Here the terms are used when discussing
repeaters and seem to be little more than a different way of distinguishing
A from B.

In the original Morse/Vail demonstration line from Washington to
Baltimore, as Vail described it (_Description of the American
Electro-Magnetic Telegraph_; also online on Google and quite interesting),
as well as one manual of telegraph codes done at almost the same
time (Rogers, _The Telegraph Dictionary and Seaman's Signal Book_, 1845).
There may, or may not, be some relationship between Vail's use and
the way in which Faraday defined "anode" (rising-sun road; east) and
"cathode" (setting-sun road; west), but it probably isn't worth going into.

So what were the conventions for "east" and "west" in landline telegraphy/tty?

Regards,
David M.
===
Dr. David M. MacMillan * dmm at lemur.com * www.lemur.com & www.CircuitousRoot.com

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