The lighter colored crossarms (painted white?) were for telephone service while the lines atop this short stretch were for electric customers.

The phone wires would have been open twisted pairs. These were individual rubber covered wires with a cloth covering, twisted together. This type of wire by the early 1920s became obsolete in favor of sturdier and more weatherproof paired wire for subscriber drops and spans between poles. In a neighborhood like you see above, combining the subscriber lines into lead sheathed cable with copper pairs undoubtedly took place in not many years after this photo was taken.