ASME-Landmark:Pitney-Bowes Model M Postage Meter

The world's first commercial postage meter—the Model M—was designed and developed in Stamford between 1901 and 1920 by inventor Arthur Pitney and entrepreneur Walter H. Bowes, with the assistance of Walter H. Wheeler, Jr. The Model M formed the cornerstone of the Pitney Bowes metered mail concept, which was officially recognized by the U.S. Postal Service and was introduced on November 16, 1920.

The postage meter, which eliminates the need for the adhesive stamp, fundamentally affected the expeditious handling of mail and rapidly came into use around the world. The meter allows the simultaneous postage and cancellation marking of a piece of mail. The official imprint authorized by the Post Office Department on September 1, 1920, is an oval indicia showing the mailer's license number, the register number of the meter, and the denomination of postage. The location, date, and time are imprinted to the left of the oval. At first, metered mail was available in 20 denominations, but today the meters can be set for the amount of precise postage required for the particular size, weight, and class of mail.

Automatic lock-out was essential to prevent thefts. Two sealed but visible registers comprise a self-checking account of postage printed. The ascending register, which is inaccessible even to Postal Service employees, maintains a running dollar-and-cent total of all postage printed. The descending register tells the user the value of postage remaining for use. As long as the sum of these registers matches post Office records, the Postal Service knows how much is owed. See ASME website for more information