| With the introduction of the D-3 and D-4 polyphase meters, the DS-2 and DS-3 switchboard versions soon followed.
In 1908, the DS-4 and DS-5 were introduced and these are identical to the DS-2 and DS-3 respectively except for the locations of
the stators in the meter. The DS-2 and DS-4 both have cast metal covers (with windows for register and disk) and the DS-3 and DS-5 both have covers with glass windows on all sides. |