Classic Computer Magazine Archive COMPUTE! ISSUE 73 / JUNE 1986 / PAGE 104


Charles Brannon, Program Editor

Printers For The Amiga

A printer is one of those optional but essential add-ons for your computer. It lets you reap something tangible from your word processor, terminal program, spreadsheet, or drawing program. True, you can use these tools to prepare files which you can transmit via modem directly to other computers. But hardcopy-type on paper-is still the only universally acceptable form of nonverbal communication.
    Commodore doesn't sell an offical Amiga printer yet.Instead, you're free to attach practically any serial or parallel printer. The Amiga sports an RS-232 serial port as well as a standard parallel printer port. All it takes is the right cable to link the Amiga with almost any printer.
    The commonly available IBM printer cables appear similar to Amiga cables, except the end of the cable that plugs into the IBM is a DB-25 male connector and the Amiga port is also a DB-25 male connector. Since printer cables specifically for the Amiga can be difficult to obtain, you might be tempted to use a "gender-changer" (a box or cable with a male connector on one end and a female connector on the other) to connect the IBM cable to your Amiga. Don't do this. Such an arrangement could damage your Amiga or your printer, or both.
    The Amiga parallel port does not use exactly the same pin assignments as the IBM port. (Refer to page 7-13 of the Introduction to Amiga manual for a pinout chart.) Even more important, pin 23 on the Amiga parallel port is a +5-volt power supply, while pin 23 on an IBM-type printer cable may be connected to voltage ground. If the cable carries this voltage, and if the printer connector has a grounded pin at that position, the power supply in your Amiga may be damaged.
    If you have a serial (RS-232) printer connected via the Amiga's serial port instead of the parallel port, a similar caution applies: Pins 14, 21, and 23 on the serial port carry power supply voltages. (Refer to page 7-12 of the Introduction to Amiga manual for a pinout chart.) Since these pins are often unused in devices like modems and printers, it may be safe to use IBM-type serial printer cables. Check the manual for your printer carefully to be sure that your particular model does not make any connection to these pins. Again, a gender-changer plug will be required to attach an IBM-style cable to the Amiga serial port. It's best to check with your dealer before using a suspect cable.

Printer Drivers
Once you've hooked up the hardware, you need to "attach" the printer to your software. Although every printer manufacturer uses different specifications for software control over printing features, the Amiga is capable of adapting to a variety of popular printers.
    What complicates things is that every printer has its own unique set of codes, even for common effects such as underlining or boldfacing. For example, the Epson MX-80 uses the ASCII sequence 27-53 ("ESC4") to turn on italics mode, and 27-54 ("ESC-5") to turn off italics. On the other hand, the Okimate 20, which is similar in many other ways, uses the sequence 27-37-71 (ESC-%G) to turn on italics, and 27-37-72 (ESC-%H) to turn italics off.
    When an Amiga program wants to print italics, it can't just use the code for one printer model, because the program would be incompatible with other printers. Instead of sending the actual code for italics, then, Amiga programs send a symbolic code for italics. If you tell the Amiga which printer driver to use, the driver translates these symbolic codes into the actual codes for your printer.
    Use Preferences to install your printer driver, following the instructions given in Introduction to Amiga, pages 7-6 to 7-11. Printer drivers currently exist for the Alphacom Alphapro 101 (no longer in production), Commodore CBM-MPS 1000, Epson FX-80, RX-80, HP Laserjet/Laserjet Plus, Brother HR15XL, Diablo Advantage C-150, D25, 630, Qume LetterPro-20, and Okimate-20. If your printer is not on this list, try some of the drivers to see if they work with your printer. For example, the Juki 5510 dotmatrix printer is Epson JX-80compatible, so you can use the Epson JX-80 printer driver.
    If none of the drivers work, select the Custom printer driver. If you have the version 1.1 operating system upgrade, by default the Custom selection looks for a printer driver named Generic. The Generic driver works with any properly cabled printer by ignoring all special printer codes. If your printer won't respond to the codes used by any of the printers on the list, you can at least get a plain-vanilla text printout with the Generic driver.
    Unfortunately, the Generic driver won't let you use any special printing effects such as underlining, boldface, italics, or bit-image graphics. You need a printer driver created especially for your brand of printer. Many people are working on drivers for unsupported printers, including one company that has developed a printer-driver builder that a nonprogrammer can use to design a new custom driver. Nevertheless, if you are looking for a printer for your Amiga, it's best to buy one that is compatible with one of the above printers.