mark@zok.UUCP (Mark W. Snitily) (08/21/89)
The following is a somewhat long note about a nice three port serial I/O card and a question about RS-232 pin orderings. With the recent info on how to fix uucico throughput with 16550A's, I went shopping for a new serial I/O card that would allow me to replace *all* of the 16450 UART chips with 16550A chips. (Typically serial I/O cards have one 16450 (or equivalent) soldered in place and have one socket for an additional UART for COM2.) What I came across was the Everex EV-170B card. Nice. Typical inexpensive I/O card; has parallel port, game port, but has *three* serial ports. Each serial port's UART is socketed and each serial port allows the selection of independent interrupt vectors and I/O addresses. In other words, this card *is not* like the typical DOS configuration of forcing COM1/COM2 to share the same interrupt vectors with COM3/COM4. So, if you have an unused interrupt vector (either 5 or 9) then you can configure Unix (386/ix 2.0.1 in my case) to have *three* serial lines. And, if you're using a device driver that supports the 16550A, *all* three lines can enjoy the super throughput that the 16550A provides. So far, all nice and grand -- now for the real reason why I'm writing this. To make what could be a *real* long story short, IMHO the pins on the card that connect to the RS-232C cables are really ordered *weird*. RS-232C J Connector Pins on Card --------------------- ------------------------ 9-pin 25-pin Signal Normal Everex EV-170B 1 8 DCD 1 (8) 1 (8) 2 3 RX 2 (3) 3 (2) 3 2 TX 3 (2) 5 (7) 4 20 DTR 4 (20) 7 (4) 5 7 GND 5 (7) 9 (22) 6 6 DSR 6 (6) 2 (3) 7 4 RST 7 (4) 4 (20) 8 5 CTS 8 (5) 6 (6) 9 22 RI 9 (22) 8 (5) For example, on the card the J connector pin number 5 normally connects to pin number 5 on the 9-pin RS-232, (or pin number 7 on the 25-pin RS-232). But on the EV-170B, the J connector pin number 5 needs to connect to pin number 9 on the 9-pin RS-232, (or pin number 22 on the 25-pin RS-232). [The above mapping was obtained only after: exchanging the card once thinking it was defective -- no difference; calling Everex tech support -- it was configured correctly according to them; buying a RS-232 breakout box -- that's something I've avoided for over a decade; and finally tracing the lines on the PC card -- it now works!] If anyone from Everex is reading this, may I suggest that you please add the pin's signals to your manual. There's no hint that buying a standard cable (from someone other than Everex) won't work. Has anyone ever seen the pin ordering that's on this card? Is it *weird*, or is it yet another standard used by some vendors? -- Mark W. Snitily 894 Brookgrove Lane Cupertino, CA 05014 (408) 252-0456 (voice with answering machine) ...!{amdcad,ardent,athertn,claris,daisy,limbo,mips,sgi,voder}!zok!mark