medin%ucbcory%berkeley@sri-unix.UUCP (11/17/83)
From: Milo Medin <medin%ucbcory@berkeley> With the discussion about the Star Gemini printers on the net, I thought many of you would be interested in some of the experiences my company has had with the Delta-10 printer. First of all, it seems to have many desirable features including graphics, and is supposed to rated at 160 cps. It doesnt keep up with a 1200 baud terminal output, even with the 8k buffer that comes with it. The head motion seems plenty fast enough, as does the linefeed, but at the ends of the platen, it just seems to unecessarily pause, greatly degrading throughput. Thus it necessitates handshaking. We used the serial interface that comes standard with the delta-10, and which I understand to be the same interface that is available optionally with the 10 and 15 series printers. Because of certain interface requirements, we were forced to use a DTR (or similar) handshaking mode (hardware handshaking). The closest thing on the printer that comes close to that is serial byte busy mode. I dont know how the software mode works but the hardware mode is terrible. Normally, the DTR line is high while the printer buffer isnt full, and its supposed to go low when the buffer is in danger of overflowing. It then is supposed to stay low until the buffer is empty when DTR returns high. Well, the printer's serial byte busy mode interface doesnt pull the line low, it pulses it low, returning high a short period of time later, not when the buffer is empty. Then, when the buffer is empty, the printer pulses DTR low again to signify it is ready again. This strange type of protocol was not compatible with the interface we were using, and after many phone calls, Star Micronics admitted this was so. The printer cannot generate 'Standard' DTR line behavior. Behavior on other handshaking lines is similar. We returned the delta to the dealer in exchange for an epson, which hopefully will be better suited to our interface. This is not to say that the parallel interface doesnt behave well, or that the XON/XOFF protocol doesnt work, we dont know we havent been able to try them as our particular application only permitted this one mode of interface. What we do know is that the delta-10 wont work in the configuration we tried it. In short, if you are planning to buy a Star printer, be very wary about interfacing requirements... Milo Medin medin@ucbcory medin@lll-mfe