This type of crossarm construction has been used for decades whenever safe openwire clearance was required from adjacent trees, buildings, bridge underpass foundations, etc., by electric and communications companies.

Also note the lead-sheathed, enclosed-pair telephone cable that ran beneath, serving subscribers along this nice residential Connecticut neighborhood. Such construction was pretty new at the time this picture was taken. Paired enclosed phone cable was more reliable than openwire circuits and eventually replaced a lot of them in later years throughout Bell System territories throughout the United states.