Path: news.uiowa.edu!news.physics.uiowa.edu!math.ohio-state.edu!howland.reston.ans.net!swrinde!sgigate.sgi.com!uhog.mit.edu!news.mathworks.com!newsfeed.internetmci.com!bloom-beacon.mit.edu!senator-bedfellow.mit.edu!pbauer From: pbauer@athena.mit.edu (Paul H Bauer) Newsgroups: comp.sys.apple2 Subject: Re: Switch settings for Apple II Pllel. Ifce. Card Date: 22 Mar 1996 02:10:02 GMT Organization: Massachusetts Institute of Technology Lines: 104 Message-ID: <4it25q$qgn@senator-bedfellow.MIT.EDU> References: NNTP-Posting-Host: arcadia.mit.edu For the apple parallel card the following was provided by Mr. David Empson awhile ago when I had the same question. Apple Parallel Card The Apple Parallel Interface Card has a bank of seven DIP switches near the top center of the card. ON is UP and OFF is DOWN. Their functions are as follows: SW1-SW3: set the strobe length according to the following table: SW1 SW2 SW3 Strobe length (microseconds) off off off 1 on off off 3 off on off 5 on on off 7 off off on 9 on off on 11 off on on 13 on on on 15 SW4 selects the polarity of the Strobe pulse: ON = negative, OFF= positive. SW5 selects the polarity of the Acknowledge input: ON = negative, OFF = positive SW6 selects the firmware compatibility: ON = "Centronics" ROM (doesn't automatically send line feed characters after carriage return), OFF = "Parallel Printer" ROM (does send LF after CR). SW7 enables interrupts if ON (and should be left OFF!) The manual suggests the following settings for most parallel printers: SW1 off SW2 off SW3 off (1 microsecond STROBE pulse) SW4 on (negative STROBE pulse) SW5 on (negative ACK pulse) SW6 off ("parallel printer") SW7 off (no interrupts) This should work with the HP Laser printer. Note that the Apple II parallel cards use a non-standard pinout on their DB-25: you cannot use an IBM PC parallel printer cable. If you don't have an appropriate cable, I can give you the pinout of the connector, and you may be able to get one made up. IDE DB-25 pin Centronics pin Function HP IIP+ 1 1 Data in bit 0 3 2 19 Signal Ground 5 3 Data in bit 2 7 4 19-30 Signal Ground 9 5 2 Data bit 0 Data 0 11 6 3 Data bit 1 Data 1 13 7 Blocked (pin must be removed from the DB-25 plug) 15 8 4 Data bit 2 Data 2 17 9 NC 19 10 NC 21 11 7 Data bit 5 Data 5 23 12 8 Data bit 6 Data 6 25 13 9 Data bit 7 Data 7 2 14 Data in bit 4 4 15 1 Strobe output Strobe 6 16 10 ACK input ACK (Out) 8 17 Data in bit 1 10 18 35 Data in bit 7 Aux Out 2 (Out) 12 19 12 Data in bit 5 Paper Error (Out) 14 20 19-30 Signal Ground 16 21 13 Data in bit 6 Select 18 22 5 Data bit 3 Data 3 20 23 6 Data bit 4 Data 4 22 24 16 Signal Ground 24 25 32 Data i bit 3 Fault (Out) 11 Busy (Out) 17 Earth 18 +5 Volts (Out) 33 Aux Out 1 (Out) 14, 15, 31, 34, 36 No Connection The other pins are not used with a standard parallel printer. Pins 9 and 10 are not connected. Pins 1, 3, 14, 17, 18, 19, 21, and 25 form an input 8-bit data bus, which can be used if the card is being used for general purpose bidirectional parallel data transfer. In order the bits are 0, 2, 4, 1, 7, 5, 6, 3. Unfortunately, I don't have any documentation on the pin numbers of the Centronics connector here, so I don't know what the input functions listed above are used for. They could be any of ERROR, SELECTED, BUSY, or PAPER EMPTY. I don't think the firmware uses them. The card cannot drive the INIT, AUTO FEED XT or SELECT pins, which may need to be tied to +5V or ground to get the printer to function properly. David Empson dempson@actrix.gen.nz pbauer@mit.edu