A method for providing a mailing system includes receiving, through a computer system, a mail item from a sender, and printing the mail item in a document including coded data thereon, the coded data including an indication of the identity of the mail item and at least one reference point on the document. Independent sessions with each of a plurality of clients are maintained, wherein the number of clients in the plurality of clients can vary over time, and wherein the start of each session and the end of each session can be independent of the start and end of other sessions. Ramp integrator to the new frequency offset.