Summary edit

This photo shows a type of 'B' Board that was used to terminate calls to a manual office from a dial exchange like Panel. An incoming call would show up on the position keys then display the digits inside the box in the middle of the photo. They were received in the PCI 'Panel Call Indicator' format. The Operator would read the display then attempt to terminate the call to the manual line. B Boards were required during the transition period to automatic dial switching from manual exchanges.

Licensing edit

	This media file is in the public domain in the United States. This applies to U.S. works where the copyright has expired, often because its first publication occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See this page for further explanation.
	This image might not be in the public domain outside of the United States; this especially applies in the countries and areas that do not apply the rule of the shorter term for US works, such as Canada, Mainland China (not Hong Kong or Macao), Germany, Mexico, and Switzerland. The creator and year of publication are essential information and must be provided. See Wikipedia:Public domain and Wikipedia:Copyrights for more details.