ocr: Classes, Objects, and Characteristics DPD implementation The physical printer dass and its objects and attributes are mapped to codes in the DPD -The attributes are set up as follows: - asking the bidirecional inlerface of the print device -loading the values from a stalic dotabase for unidireclional Nefworking print device object attributes are determined by issuing printer-specific commands, control sequences, and queries 1o the print device and receiving a response through back-channel monitoring. Figure 7