On 05/07/2008 08:08 PM, James Knott wrote: > NoOp wrote: >> I've a few of those, and 8251 USART's out in the garage... I know the >> 8251 could be configure to allow 1.5 stop bits, can't recall if the 8250 >> also had this option. However, 1.5 was only used for characters with 5 >> information bits, so it wouldn't apply to standard/modern modems anyway. >> >> >> > > On the 8250 and later, you specified the number of data bits and stop > bits separately, so it was possible to have any combination of data bits > and stop bits. However, in all my years of experience with working with > this stuff, I have never, not once, seen 1.5 stop bits used with 8 bit > codes. It's always been either 1 or 2 stop bits, though 1.42 and 1.5 > were common with 5 bit codes. I've also never seen a UART that could do > 1.42 stop bits, which is found only on mechanical devices. A UART would > be configured for 1.5 stop bits, which isn't much of a difference from > 1.42. So, while it is technically possible to configure for 8 data bits > and 1.5 stop bits, it's never, to my knowledge, ever been done in > production systems, as it doesn't comply with any of the standard > codes. As I mentioned in another note, this is one area, having worked > for 36 years in data communications and computers, that I have a *LOT* > of experience. In fact, when I designed & built that 8 port serial card > I mentioned earlier, I found a bug in the 8250 that National > Semiconductor didn't know about. I even got a nice letter from them for > finding it.
Well we are *well* OT on this thread aren't we? But while we are; I've never heard of 1.42 stop bits use in any modem technology. Yes, in telegraphy, but not in *any* modems or any other telephoney networking situations. So back on 1.5SB: I seem to recall that it was quite useful in the 8251 for communications with teletype and selectric interfaces. Of course I could be wrong, it's been 30 years or so since I designed circuit boards to interface between that chip and my noisy mechanical printers at the time. Hey, I used to refurbish brass bar cash registers as well... does that count? :-) I recommned that the nostalgia bits of this thread end. I'd much rather like to know if the OP ever managed to download OOo and get it working. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
