In addition to telephone, telegraph and electric lighting service lines that were strung along city streets of the United States during the later part of the 19th century were pole and "sawhorse" style crossarm structures that supported wires for the forementioned services from building-to-building. In particular some of the pole style can be seen in this image.

One really wonders what kinds of rare and colorful glass insulators were used in these installations. Especially here in the Boston vicinity where some very colorful insulators in unique designs were manufactured!