Shorpy is a great source of images from the distant past. Quite a number of them deal with topics of interest to networking enthusiasts.
Here is one such example that dates from circa 1919 and takes a "behind the scenes look at communications tech some 80 years after the telegraph tapped out its first message."
To really appreciate the detail one should look at the large version of the picture available from the
original Shorpy post. The comments left by Shorpy readers are usually also worth reading to gain a deeper insight into the details depicted in the photo.