Mac OS: ASCII vs. Binary Encording, How this Affects HP Printers

When you send information over a network the raw data needs to be encoded to ensure a quick and reliable delivery. The two types of encoding used are ASCII and Binary.

ASCII encoding converts all of the raw data into a string of ACII (or plain text) characters. This is the oldest method of encoding and the most universally supported. The only draw back to ASCII encoded data is that sometimes the encoding can actually cause an increase in the amount of data that needs to be transmitted. That's where Binary encoding comes in.

When data is encoded as Binary the resultant stream is not restricted to the ASCII character set. This can produce a much smaller amount of data to be transferred and results in quicker network performance.

So how does this affect printing to an HP Printer?

Until just recently it was not possible to print Binary encoded PostScript jobs to HP printers if they were not connected either Parallel or via AppleTalk. This is because the printer firmware made certain assumptions based on connection type. The printer FW assumed that data coming over LPR/LPD or port 9100 would never be binary encoded. That is why setting up to the printer via IP would always fail.

Since this was a printer firmware (FW) issue we tried for many years to get them to correct this by actually analyzing the data as it arrived and determining what the encoding method was regardless of connection type. This did not seem like it was ever going to happen. So JetDirect implemented a "work around" that would allow Binary encoded postscript to be processed when the connection was over IP. What they did was implement a new LPR queue called BINPS (BINary PostScript). When a job was sent to this LPR queue the JetDirect card would flag the data as "binary". Because of this the printer would properly read the Binary encoded data and process the file. This was our only solution for a few years.

Then the printer FW team stepped up (thanks Quark Xpress for Windows) and decided that auto detection should indeed occur in the printer. So this feature was added to the OZ firmware code base. This meant that printers such as:
4200
4250
4300
4350
4600
4650
5500
5550
9000

would be able to accept binary encoded data through any connection type. But this is currently only true of OZ based printers.

So this leads to the question of USB connected printers.

Why does binary PS fail over USB. Well, the answer is directly above. There really have not been any OZ printers with USB ports except the 2300/2400, 3700 and now the 4650. Each of these printers will work with Binary PostScript over USB. None of the other USB on board printers have the auto detection feature and will fail this includes the recently released 1320.