Flash Memory (SIMM, DIMM) / Hard disk
For the use of own company fonts or the use of forms these can be stored in the printers in so-called flash memories or on hard disks. These memories are non-volatile and are retained even after the printer has been switched off. The advantage of this memory is that the fonts or forms can only be loaded once and then used as often as desired. On the transfer paths to the printers, the font or form data is only loaded once when on the move.
This advantage of the flash memory has to be bought in the truest sense of the word:
- Each printer requires an additional, chargeable, printer-specific memory module, which must be purchased again and again when the printer is replaced.
- If the fonts or the content of the forms change, they must be reloaded into all printers. This process can only be automated to a limited extent.
- Especially when using printer types from different manufacturers, the loading processes are different and require different procedures. The data to be loaded may also have to be processed differently.
- Many inexpensive printers do not have the possibility of memory expansion with a flash memory or a hard disk.
The increasingly broadband network connections to printers open up an alternative to the use of flash memories: loading the required fonts or forms together with the user data. Of course, only the fonts and forms that are really needed are loaded. Of course, they are only loaded once during a printer session.
The Flash converter manages a pool of fonts and forms that is practically limited only by the size of the hard disk (the size of the computer on which the converter is running). All printers can use this shared pool, so that when a form is changed, a file is exchanged, which is then immediately used by all printers with the next print job. Of course, this also applies to printers that are not switched on at this moment.
The Flash converter also includes an emulator for the Printer Job Language (PJL). The Printer Job Language is a collection of commands for controlling laser printers. In addition to complete job control, PJL also offers extensive status controls.
The printer can either report its current status in response to a request from the printing computer, or send a new status unsolicited when certain events occur, such as the end of paper.
Using the PJL protocol, a printer can be precisely controlled by the printing computer and the printing progress can be monitored. A prerequisite for the use of PJL, however, is a bidirectional network connection. In the TCP/IP network, PJL can therefore only use the RAW protocol as the transmission protocol - LPR/LPD does not support printer feedback.
The PJL protocol is used by IBM AS/400, iSeries and i5 series computers to communicate and control printers. The network connection is established via a RAW connection.
Most laser printers are inherently capable of supporting PJL and can therefore communicate directly with the IBM system. For matrix printers or label printers, PJL is rarely available. For this group of printers, the converter can be used to connect them to the IBM systems.
The flash converter also has a programmable filter that allows changes to be made to the data stream received. Single characters but also whole character sequences can be recognized and removed or exchanged.
Using this filter function, control sequences can be changed for specific printers, such as the order of the paper trays or the adaptation of character sets.
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