At 05:52 -0700 8/11/10, John Carmonne wrote: >I have a G4 Cube and PM G4 MDD both boot OS9 and I use a program to >communicate data to CNC machinery. The method was always via printer or modem >ports on the pre G4 machines with those ports. So the G4's have USB and I need >to transfer the files via Mac to a RS232C hub connected to 8 CNC machines. The >communication program has all the setup configurations, however only affords >either printer or modem port. Is there any hope of making this work.
- - - I have been using an old Mac SE/30 for that kind of thing. OS 7.5 talks to OS 10.3.9 quite well on ethernet but you can't use Tiger. With OS 9 you'll be fine. But you should be warned that RS232 has been modified in usage more or less recently. USB to RS232 converters, especially those that use power from the USB bus at +5 volts claim to be RS 232 compliant but they are not if you read the RS-232C standard which is all I can afford. The problem is that the new stuff doesn't go negative to represent a mark (logic 1) condition. It just goes low enough, about +100 mV, to look like a logic low to a modern CMOS gate. Your CNC machine or hub may well requite a voltage below -3 V which is the RS 232C standard. Mac serial ports are fine with that. I have also used a 1.5 volt dry cell in series with the TxD data line polarized to subtract 1.5 volts from the fake RS232 signal from the USB->RS232 converter. Something else I find useful is a cheap Intel box that's just good enough to run Linux and still has serial ports. Linux is comfortable with OS-9 and all versions of OS neXt over Ethernet. If you're willing to learn some perl have a look at <ftp://ftp.macnauchtan.com/Excel/Tektronixwaves.pl>. It goes the other way, reading from an oscilloscope over RS-232 but might be a starting point. -- --> If the US citizens between 18 and 21 would exercise their right to vote we wouldn't have a 21 year drinking age. <-- -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
