Apparatus Blanks for 500-series Telephones

RELATED PAGES ON THIS SITE: WE 500-series WE 300-series COLORS Dial Desk Phones

Apparatus blanks were used to fill the space in the housing when a dial was not needed for several reasons including:

In 1949 when the 500 series was announced, some 25% of telephones in the Bell System were still served by manual (non-dial) exchanges.
Restriction on dialing out to control measured local or long distance charges.
Phones on PBX lines, where outgoing calls were made by operators only, such as in in companies or hotels.
Extensions connected to pay phone lines in small retail establishments.
Phones used solely for connection to a messaging or reservation line (e.g. using a 43- or 53-type dial to automatically call a taxi company, hotel, airline, etc.)
Private phone systems (intercoms).

For more information, see BSP C34.401 and
"APPARATUS (DIAL) BLANK DESIGN FOR THE WESTERN ELECTRIC 500,"
by Russ Cowell and Paul Fassbender in Singing Wires, March, 2009.

Thanks also to Carl Bennett for application suggestions.

Apparatus Blank in Set	Apparatus Blank Back	Description
95A		95A Apparatus Blanks were used in early soft plastic housings. They would only fit in the housings for desk sets, not in the "new" wall or keyset set types.
95B		95B Apparatus Blanks came out in 1954 to fit the various models being introduced in the 500-series. The smaller metal bracket was an obvious cost saver.
		The bracket had to mount to the housing of the wall set to permit the housing to be removed and installed over the cradle. The blank attached to the bracket using a single screw in the blank's center.
95C		95C Apparatus Blanks appeared in about 1967, and were cost reduced to eliminate the metal bracket completely. The tabs sat on the unused dial mounting brackets in all 500-series sets. Larry reported that later 95Cs eliminated the posts projecting from the back. The 95C sat a bit flusher with the housing than the 95B blank.

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