On Thursday 26 February 2009 18:55:22 William L. Maltby wrote:
On Thu, 2009-02-26 at 16:55 +0000, Anne Wilson wrote:
On Thursday 26 February 2009 13:37, William L. Maltby wrote:
<snip>
Feb 26 12:12:25 borg2 kernel: serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A Feb 26 12:12:25 borg2 kernel: serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
Didn't you say there was only one port? There might be a second on the main board that is accessible via a header. If it's not hooked up disable all but the first in the BIOS (later). It's not really hurting anything as is, but it will free the I/O address and IRQ for assignment to other devices.
I believe you are right. I remember those - and the 25-9-pin adapter :-). Peering around the back in a dark corner, I could well have been mistaken. OK - female socket, so that's a COM port, I think.
To be politically correct and eliminate ambiguity, we'll change the terms here. Socket (formerly female connector) on the computer s/b a parallel printer port. Almost always a 25 pin in the past, but I've not kept up with that stuff over the years.
Plug (formerly male connector) on the computer s/b serial ports.
On the cable, this is reversed, of course. Now if the cable has RS-232 on both ends and is not a fully symmetrical null modem cable, it will make a difference which end is connected to what. Make sure your cable socket end is what's hooked to the computer. Often the cables will be labeled which end goes to computer or device.
Sometimes cables have the same gender on both ends. If they've done that you could just have the cable reversed (presuming it's one of the asymmetric cables). It's not uncommon for a null to be made by jumpering certain pins on just one side of the cable and crossing 2 and 3 end to end.
Now I'm really confused. The BIOS definitely only shows one COM port. To be
Ouch! Since I've not kept up with this stuff I can't sat if there are other new devices which use 16550 serial drivers. _But_, there are definitely 2 ports as the detection routines must write to the ports and read status to determine if it's a 16450, 16550 and revision A or not (the original 16550 had insufficient buffer IIRC and the A had to be issued to prevent overflow at higher speeds. CPUs "back in the day" were just to slow to handle the interrupts quickly enough).
My guess is that your BIOS has a "menu" in the legacy devices area that has a drop-down or scrollable menu to select which port to configure. In there you can enable/disable, change default I/O and IRQ settings, etc. I think you'll find a second port defined.
OK - so far I've had to do this in short spells, which is definitely not the most productive. Hopefully tomorrow I'll get a good long spell when I can check out manuals both for the motherboard and the UPS.
Which raises the possibility of the computer's connector being on ttyS1 instead of 0.
I can change the config files and try those, too.
But I suspect if you check the back of the computer you might see two plug connectors. These should be the serial ports. In today's world, probably 9 pin.
honest, I can't remember whether I connected it or not. I guess I ought to open the box and see what's what, but not today - it's already too late to do that.
Where's your dedication?! Where's your glass of wine?! Not at the same location?! Time to leave I guess! :-)
Oddly enough my husband can get quite tetchy if I spend more than 12 hours a day with a computer :-)
Feb 26 12:12:25 borg2 kernel: 00:05: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
Is this what I'm looking for? I don't see anything else.
Yes. That means that all is as expected (i.e. as _I_ expect).
Ctrl-A Z - yes, I found that.
In one of the menus from there, IIRC, you can set baud rate, parity, flow control, etc. BTW, someone mentioned UPS. Really dumb ones don't send anything except a power loss or battery low indication. Old ones used to do this just be controlling DTR (IIRC) and you couldn't "see" anything until it was raised. I don't know the details of yours (if it is a UPS) but there should be some docs or a CD that describes a minimal amount of that information. Or maybe they expect WinBlows and just put that information in a help menu.
In the 'User Manual' that comes with it there is no such info, as far as I can see. There's a 120-page manual on the CD. I'll examine that tomorrow. However, at a glance, it seems to expect you to set things up with its own gui software. Since there is a Linux setup section, I'm guessing that it runs in a browser. Again, I'll give it my attention in the morning.
BTW, someone mentioned RS-232C. That's the cable and electrical specifications. RS-232D is the connector specifications for a "D" shell connector. They don _not_ conflict. They are just different parts of the same overall specification. So you need have no confusion if you see us reference the seemingly conflicting specifications.
Being only moderately geeky, I just think of RS-232 as serial connection - I don't know the details :-)
Settings at present:
A Serial Device : /dev/ttyS0 B Lockfile Location : /var/lock C Callin Program : D Callout Program : E Bps/Par/Bits : 38400 8N1 F Hardware Flow Control : Yes G Software Flow Control : No
Hardware flow control is suspect _if_ the device doesn't allow flow until some event is seen, e.g. DTR or DCD and/or some information from the device is ready to be transmitted. This could make it look like nothing is working. But that really depends on how the device is supposed to behave.
Unless the device can send large amounts of data or requires flow control, you might try disabling it.
OK - I'll look at that, too.
I'm not often beaten by things, but sometimes I have to fight them on and off for quite a while before they are resolved. I'm grateful for all the help I'm getting here. I shan't be giving up for a good while yet :-) if at all.
Anne