kamesh@bmsr7.usc.edu (Kamesh V. Kothuri) (11/27/90)
Hi Everybody, I am having a problem with the serial port on Apple Laser-Writer II NTX model printer when I try connecting a SUN Sparc station or an IBM PC-AT on its serial port. The printer uses only TD,RD and GND on pins 2,3 and 7 respectively. I have tried both a null modem cable in which lines 2 and 3 are crossed and one which is straight. Neither worked. 1. When I send something (an ordinary text file or a postscript file using both cat file >/dev/ttya and lpr commands) from the system, the green LED on the printer blinks for quite a while, but doesn't print anything. Doesn't even feed the paper. 2. When I put the printer in DIABLO mode, it feeds several pages but again doesn't print anything. 3. When I redirect a postscript program given in the manual on to the printer the printer receives it properly and executes it and gives me the expected printout. 4. The printer works fine on appletalk. We are trying to move the printer from an apple talk network on to the SUN Sparc station and we are facing this problem. Tried another similar printer too. Even that behaves exactly the same. I recollect, initially I tried connecting the printers onto a Sparc 390 server on ttyb which is a 9 pin DB connector with all the pins connected. Does any other signal on the DB9 spoil the RS 232 on the printer? But then, why does the postscript program given in the manual work? I am confused. A replacement board costs about $760 plus taxes in our University stores. It IS a huge sum, considering connecting two printers to two different SUN workstations. Could anybody out there, have any ideas as to what could be done? Apple doesn't directly talk to the customers and their dealers, here in Los Angeles area are of not much help in this regard. Any help in this regard is highly appreciated. kamesh. kamesh@bmsrs.usc.edu kothuri@aludra.usc.edu
cbradley@blackbox.lonestar.org (Chris Bradley) (11/27/90)
In article <28411@usc> kamesh@bmsr7.usc.edu (Kamesh V. Kothuri) writes: > I am having a problem with the serial port on Apple >Laser-Writer II NTX model printer when I try connecting a SUN Sparc >station or an IBM PC-AT on its serial port. > The printer uses only TD,RD and GND on pins 2,3 and 7 >respectively. I have tried both a null modem cable in which lines 2 >and 3 are crossed and one which is straight. Neither worked. The LaserWriter most definitely will use the DTR signal for "hardware handshaking." The poster does not mention what the asynchronous communications parameters settings are, but even the NTX cannot accept a continuous input stream at 9600bps. In this case, I would recommend adding support for DTR to the cable that connects the NTX to the Sun, which is pin 20 on the normal EIA RS-232-C connector. The LaserWriters can also be set to use XON-XOFF ("software") handshaking, which doesn't require DTR. This is supposed to be done with a short PostScript program that gets downloaded to the printer, but I don't know what that is. -- Chris Bradley | "I confess freely to you, I could never look Businessland Advanced Systems | long upon a monkey, without very mortifying Dallas, Texas US | reflections." cbradley@blackbox.lonestar.org | -- WILLIAM CONGREVE 1670-1729