It is quite possible that this line (on the left) started out as a 6 pin one and the 10-pin crossarm added later on. I've seen a lot photos of early lines with the above type of pole line construction. In addition, the oldest lines (1900 or earlier) appear to have been constructed by six-pin crossarms. As more telephone subscribers came on line more circuits were obviously needed and 10-pin arms seem to have become the standard not too long after 1900.

Lines providing electric lighting service are seen along the right side of this photo.