bryan@cs.utexas.edu (Bryan Bayerdorffer @ Wit's End) (02/16/91)
I've just connected a brand-new QMS PS-410 laser printer to my A2500/30 (rev 4.5 motherboard) via both the parallel port and one of the serial ports on a 2232 multiserial card. While the serial connection works fine, I'm experiencing problems when sending postscript files over the parallel connection. The problems only occur when sending data at high speed, e.g. when copying a file on disk to the parallel port. When sending postscript more slowly, e.g. sending the postscript generated by ProDraw directly to PAR:, correct output is produced. This would suggest that there is some sort of synchronization problem. According to the pinout diagrams in the rather sparse QMS manual, everything is wired correctly, but I'm wondering if there isn't something funny about the Amiga's parallel port, or the printer's or both. I've verified that the infamous +5V on pin 14 is definitely not the problem, and it would appear that at least DATA0 - DATA7 and STROBE are functioning correctly. The QMS manual contains the following mysterious quotes: 1. "When wiring the [parallel] interface, be sure to use a twisted-pair cable for each signal and never fail to complete connection on the return side." 2. "Data transfer must be carried out by ignoring ACKNLG or BUSY signal." The Amiga parallel port is a DB-25, and the QMS is 36-pin Centronics. I'm using a standard PC-clone-to-Centronics cable. While quote 1 surely has to do with noise supression, I'm puzzled by quote 2. Is this telling me that there isn't any flow control (i.e. assertion of BUSY) on the printer's parallel port? That would be really weird. The QMS tech support people tell me that when the PS-410 is connected to a PC clone, the parallel port needs to be configured for "infinite retry." Apparently there is some sort of timeout on the PC side, but the QMS guy couldn't tell me how the flow control was actually supposed to work. I'd appreciate hearing from anyone who's gotten a QMS, or indeed any parallel printer to work with the Amiga and knows what the problem might be. ----------- I'd be content to use the serial connection, except for the fact that I can't get things like the AmigaDOS 'copy' command and SKsh's 'cp' to open the serial port to which the printer is connected with anything other than the default preferences settings for baudrate and handshaking protocol. I have a 2400bps modem connected to port 1 (SER2:) on the 2232 at 2400 baud, RTS/CTS, while the printer is connected to port 2 (SER3:) and wants 19,200 baud, XON/XOFF. AdvManyThanksance, Bryan