The Western Electric 202 telephone was the first widely distributed Bell System phone which adopted the use of a single handset. While the handset was developed for operator and repairman used by 1878, it wasn't until 1927 that the entirely new telephone was introduced. This set, commonly called the "round base 202" was marked as "B1". A prior "mixed-breed" set was used as an interim made up of old type 51 candlestick bases attached to a new handset cradle with an E1 handset. This set was a model "A1A", now commonly referred to by collectors as a "double A one" deskset.
The "B1" was made of sandblasted cast metal based with a black "japaned rubber" finish. They were shipped with leather or felt bases. In 1930 the "B1" was redesigned with an elongated cast aluminum base made to compliment the long handset. This set was coded as the 102 for sidetone sets and 202 for anti-sidetone sets. The dial was also recessed into the front of the phone as opposed to sitting on the frame as was with the "B1". Placing the dial "into" the phone made redesigning the dial a necessity. The new dial (4H) had to have a recessed fingerstop.
Like the candlestick phone, the 202 contained only the switchhook and switch. The network and ringer were contained in a subset which was mounted on the wall. The "B1" was generally connected to the older subsets. With the advent of the new anti-sidetoned 202 ovalbased phone, subsets contained a new 101 induction coil (this was the same coil that was used until the WE 500 set was introduced).