A postage meter is a device that produces an imprint that is a substitute for both the postmark and postage stamp.
The PB code identifies the meter manufacturer: Pitney Bowes
The letter O before a meter classification indicates that
meter text includes "U.S. OFFICIAL MAIL."
(Example Needed).
(Example Needed).
(Example Needed).
(Example Needed).
(Example Needed).
(Example Needed).
Locy System for Classifying Naval Postmarks, As Revised ©, of the Universal Ship Cancellation Society is excerpted and reprinted with permission.