In article ,
"COLIN LAMB" wrote:

I never thought about this until the matter came up in the HQ-145 thread,
but what was the process of sending messages over the telegraph lines?

Suppose I was in a small town in Oregon and wanted to send a message to a
small town in Nebraska? Is the message "broadcast", or does it go to a
clearinghouse? Can anyone on the "wire" listen in? Are there relays?

The signalling is "point to point", and there would have to be relays
to cut the effective line capacitance into manageable chunks in order
to get a reasonable transmission speed.

The military method was "outstations" to "signal office", then "office
to office" and finally to the recipient. Paper copies of the traffic
would exist at each office, and be destroyed once the message had "cleared"
(I.e: been transmitted to the next office in the chain and been
acknowledged as having been received correctly.)

They also used multiple sets on a single pair for long runs, and yes:
all the intermediate stations could hear the traffic - otherwise they
wouldn't know when there was a gap in the traffic into which they could
insert the offer of a message to another station.

A lot of civil traffic would be in code anyway - not to make it unreadable
by the telegraph staff, but simply to cut transmission costs by having 5
character groups to represent standard words/phrases/paragraphs of contracts,
etc.

I have been a ham for almost 50 years and I have no clue. There must be
some OT who are just waiting to tell me, or know a good website.

I've got some books on (the military side (British)) telegraph line
construction and operating procedure, but not the civil side.

Chris.

--
"People in general are not fundamentally stupid."
"Cite?"

Robin Munn & Simon Cozens in the scary devil monastery