scope:

This document specifies the electrical, data and timing interface between the control unit of a postal sorting system and an ink jet printer connected to that system. It further specifies an ancillary interface to the printer, which can be used for the support of remote diagnostics and other service functions. NOTE 1 This specification can equally be applied to the interfacing of printers to sequencing systems and combined sorting and sequencing systems. It was primarily developed for application to ink jet printers, but could be applied to printers with similar functionality that make use of other printing technologies. At the physical level, the specification is based on the use of a combination of a standard 100 Mbps Ethernet connection for the transfer of data and patch cables for signalling. At a logical level, data is transferred using messages transmitted across the Ethernet connection using three TCP/IP sockets, with the execution of timecritical functions being controlled through the use of signals on a TIA/EIA-422 interface. NOTE 2 Several printers can be connected to a single sorting system. In this case, the printers can optionally share access to a single Ethernet network, but each requires its own patch cables. This standard does not support the connection of a single printer to multiple sorting system control units. This document defines all messages that may be transferred via each of the TCP/IP sockets, specifies printer behaviour on receipt of these messages and defines how the timing of this behaviour is controlled by the TIA/EIA-422 signals. The specification supports the use of the printer to print bar codes, human readable text and/or images on mail items whilst these are being transported past the print head3. It provides explicit support for Bar/No Bar (BNB), Bar/Half Bar (BHB) and four state bar codes, but allows full user control over the specification of bar patterns to support more complex bar coding formats. NOTE 3 Printers that comply with the specification are required to support printing of the three above mentioned bar coding formats, character printing and two images; support for additional formats and a greater number of images is optional and, in particular, can depend on the available printer memory The different TCP/IP sockets have different functions that may be fulfilled by different subsystems referred to as sorter control, print control and remote service. Where these are implemented as distinct subsystems, they will need to intercommunicate. The interfaces between them nevertheless fall outside the scope of this specification and are not covered herein. EXAMPLE Before initialisation, during printer OFF mode and if a fatal error is reported by the printer, print control should desist from sending print instructions to the printer. It therefore needs to be kept aware of printer status. Similarly, print control might need to forward print error information to sorter control. Use of the control and service sockets also needs to be coordinated, since new initialisation messages or new software downloaded from remote service will overwrite initialisation settings and software from sorter control, and vice versa. This specification does not address the physical construction of printers or their mechanical integration into sorting systems, neither does it specify electrical power connections to the printer. This document includes three annexes and a bibliography. Annex A is normative; Annexes B and C are informative.