Actually, the other lines on the serial cable are probably less effected by the length than the 3 minimum lines used for data since these should have a lower effective bit rate on them. The thing that limits the length is primarily a rounding-off and widening of the nice square digital signals on the line. This increases with capacitance in the line which is greater with longer lines. The longer the line - the wider the pulses become at the far end of the cable. At certain speeds, you can imagine that the pulses begin to overlap each other until the decoder on the other end can't tell one pulse from the next. Pardon the oversimplification. At higher speeds, the pulses and the spaces between them are smaller. So the deformation becomes an issue sooner. In the end, the cable is perfectly useful so long as you send data slowly enough that the pulses can be differentiated. This is something of a trial and error thing unless you can hook up a scope and look at the waveform on the far end. You can probably use the cable at 300 bps with no problem. Probably even up to 2400 or higher - it depends on the cable. Try it.... Remember that many amateur radio operators still communicate at 1200 bps via packet radio and even MUCH slower rates like 100 bps on HF radio teletype links. It all depends on the nature of your communication needs. What can you use it for? Hook up an old XT as a text terminal to a multi-user system like Linux or FreeBSD. Or maybe take an old XT, CoCo or C64 set it up as a data acquisition device or remote control device and communicate to it with a terminal program on another computer. Or use it to send data to one of those LCD displays. If you get a big enough one, you could duplicate that short-lived Japanese project that displayed pager messages on the side of a sky scraper. Lots of uses, so long as you take into account the limited bandwidth on the cable. So it doesn't conform to the standard - but I think the standard is also for up to 115,200 bps. Have some fun with it. Bob To unsubscribe from SURVPC send a message to [EMAIL PROTECTED] with unsubscribe SURVPC in the body of the message. Also, trim this footer from any quoted replies. More info can be found at; http://www.softcon.com/archives/SURVPC.html
