More Info... (Win95/98/Me)
This little section gives screen shots & describes the use of this applet. A similar result can be obtained with any
OS by sending "ati0i1i2i3i4i5i6i7i8i9" (no quotes) to the modem from a Terminal
program whilst NOT online.
How to get there
This applet should be used whilst the modem is NOT in use.
open My Computer
A screen shot of my own system is shown at right. What is being shown is not the modem itself, but rather the modem software driver which allows the computer to talk to the modem. Windows® gives these drivers a name which normally (not always) is similar to the modem.
open Control Panel
Points to check:
- Is there more than one modem driver? Unless you know exactly what you are doing there should be just one modem driver to one modem. Having, as an example, two sets of drivers on the same com(munication) port can cause both drivers to be inoperative.
- "Cannot Detect Modem" Duplicate and/or multiple modem drivers is almost certainly the reason for this message. In particular, you will find that the modem listed within the General page of DUN Properties is one that is either not working and/or missing. Fixing this falls into easy & difficult varieties:
- Easy Fix: if a driver upgrade has caused a name-change, there should only be one driver here, & it is a simple matter of re-selecting the correct driver within the General page | Connect using... section of DUN Properties for each connectoid.
- Worrisome Fix: Sometimes one of the multiple drivers works, & selecting that one as in the easy fix will restore connections
- Difficult Fix: Much more often, none of the multiple drivers will work properly. It is tempting to use the 'Remove' button on the General page of Modem Properties for the none-working drivers, but usually these will reload from it's INF file the next time the machine is started, and the Registry & Hard Disc are left littered with rubbish even if the INF file is also removed.
Much better is to search out an uninstall file for all the drivers, restart the machine & reinstall the modem from scratch. This can be a long, tedious affair, so good luck, but remember - some form of registry corruption almost certainly caused extra drivers to reload in the first place, and that needs fixing, or it will all happen all over again.
- Wierd Fix: It may be that the problem is actually due to corruption in DialUp Networking, & not multiple drivers at all, in which case start here.
- Check the COM port Some old communications software does not work unless the modem is on Com ports 1, 2, 3 or 4.
Another issue to consider is
- If the mouse [or anything else] is on ports 1 or 3 then the modem wants to be on ports 2 or 4.
- If the mouse [or anything else] is on ports 2 or 4 then the modem wants to be on ports 1 or 3 (but also see below).
A typical symptom of this problem would be a fatal exception or system freeze whenever the serial mouse was used during connection [PS/2 mice do not occupy a com port]. This is because ports 1 & 3 share the same interrupt (4 in my case), as do ports 2 & 4 (9 in my case). This can cause endless problems.
An obvious question with interrupt sharing is - why? Briefly, in the early days of the Windows platform interrupts were in short supply, and the designers used interrupt-sharing to be able to provide 4 communication ports. As the hardware evolved a way was found to provide more interrupts but, in the interests of backward compatibility, Com port interrupt-sharing was maintained.
Fortunately, soft modems usually contain a virtual Com port & with plug 'n' play will obtain an interrupt that does not clash with the standard interrupts enumerated above. The More Info... button (below) can be used with each Com port to determine if your system is suffering interrupt clashes - each Com port with a device attached must have a unique interrupt and unique address. Devices on Com ports which share interrupts and/or addresses must not be used at the same time.
Obtaining the Info
Highlight the com port that the modem is on & press the More Info... button. A little dialog will come up and, if everything is OK, in a few seconds the dialog as at right appears:
The first point about this from a trouble-shooting point of view is that it has appeared without error messages and that lots of information is shown - success! (some of the Responses may well be "error" - this is normal).
The second point is the actual information.
- go here if there are errors
- Port, Interrupt & Address
The basic issue is that the modem needs a unique port, interrupt & address to function correctly. These should have all been provided correctly and automatically when the modem was installed in the machine.
The UART sits between the computer's central processing unit (CPU) and the modem. It is therefore a device which works in 2 directions: it takes the data-stream from the modem & pumps it into the computer system, & takes a data-stream from the cpu & pumps it into the modem.
Data is normally compressed by the modem before transmission, & the internal data-stream is often therefore much faster than the rate of modem-to-modem communication. Thus the UART needs to be fast enough to cope with this data-stream, and the computer needs to be fast enough to cope with both the UART data-stream & also all the other work it has to do. This is complicated by Internet Explorer 4.01 [or 5] - resource-hungry beasts which can convert a sprightly, if middle-aged, computer into an old man with arthritis at the press of an install button.
The UART can be therefore be either too fast or too slow:
- Too slow The advice from Microsoft is not to attempt communications above 9,600 bits/s if the computer is fitted with a 16450 or 8250 UART due to the likelihood of data loss (serial over-runs).
- Too fast If the computer is an older, slower model it may not be able to cope with a very fast UART plus all it's other house-keeping tasks. This results at best in data-loss (over-runs) & at worst in system errors - perhaps the dreaded Blue Screen of Death. Both the UART & the communication speed will need to be switched to a lower setting.
16550 UART's are capable of a 115,200 bit/s DTE speed (see below), which is required for V.90 connections. Later UART's, fitted in more recent computers, are capable of even higher speeds.
- Highest Speed
This is the speed of communication between the computer and the modem provided by the UART and, as a rule of thumb, generally wants to be twice the maximum possible connection speed. This matter causes a lot of confusion, and I'm grateful to Douglas Haire & Dave Lyle for their input on this.
There are two speeds where modems are concerned:
- DTE - Data Terminal Equipment : serial port speed
- DCE - Data Communication Equipment : modem to modem speed
Thus, "Highest Speed" refers to the DTE speed - the UART speed - and not to the modem connection speed. If, on connection, Dial Up Networking (DUN) reports a connection speed of 57,600 or 115,200 bit/s then it is wrongly reporting the DTE speed rather than the DCE speed. Go here for more information & a fix.
Modem connection speeds can be reduced in actual practice by a too-slow UART speed, but if the notes on UART's above are read it will be realized that both the UART speed, computer cpu speed and modem connection speed need to be matched to each other.
To set the DTE speed
- click on the General tab
- highlight your modem & press the Properties button
Soft Modems add a further twist to the tale, in that they often implement the UART and/or com port in software (a virtual UART and/or virtual Com port). This will be a disaster if the computer's CPU is too slow, or if there are system-errors.
A correspondent has pointed out to me that some soft modems are softer than others, in that Controller-less modems move only the controller functions (e.g. AT command parsing and Compression/Error correction functions) into software, whilst other soft modems put the whole damn lot there, consisting sometimes of nothing more than a PCI interface & DAA on a board. This means that virtually every function of a modem is handed to the cpu to perform, and some cpu's are not up to it.
AMR (Audio Modem Riser), CNR (Communications & Networking Riser) or MDC (Modem Daughterboard Card) modems are yet another variant. These cheap little devils (beloved of OEM computer suppliers) contain a DAA (Data Access Arrangement) on the card - allowing access to the telephone network - and, basically, that's it. The motherboard contains a DSP (Digital Signal Processer) chip which is used by the modem software, but everything else is soft, soft, soft.
One difficulty is to know that you have a soft modem, as some manufacturers seem shy of identifying their modems as such. Clues include:
For those who like rules:
- If the computer has a 8250 or 16450 UART set the com rate to 9600 bits/s max.
- Set the DTE [Highest Speed] to twice the anticipated DCE [connection] speed
- Experiment with reduced DTE and DCE rates on 486 & slower-pentiums until you find a combination that works
- 32 MB of RAM is a true practical minimum for Internet Explorer 4/5, & 64 MB is better
- Do not put a soft-soft modem on anything less than a 350 MHz cpu
- Windows 2000 systems need at least 64 MB RAM - less may result in system crashes
Soft Modems - Operating System Errors
The final issue, particularly with the soft-soft modems, is the integrity of the operating system. As these modems rely on the OS to do the business-end of a modem, any endemic systems errors will have direct impact on the functioning of the modem. Cynics will say that this is a good reason for not putting a soft modem into a win95/98/Me OS (drivers to host soft modems on Linux are now appearing - see the PC-Tel 1789 56k HSP as the first example; see also Ambient MD563X-HaM, Lucent Mars, & Smart Link HAMR5600TM).
PCI Bus (includes AGP and/or ISA) Problems Soft modem operations are time-dependant during connection and make heavy use of the PCI bus. There are known problems with certain graphics cards and sound cards which will intefere with this use of the PCI bus.
Clues & ways to check for OS errors are:
- Blue-Screen-of-Death/System Errors with other applications
- Adding DirectX7 to a DirectX5-certified graphics system (personal experience)
- "LoadFailed", "DEVICEINITFAILED", "INITCOMPLETEFAILED", etc. within Bootlog.txt - this text file is created by bringing up the boot-menu at startup:
It is, of course, also normal to see these errors within any log file!
- (win98) Hold down the Ctrl-key whilst the computer starts
- (win95/98) Press the f8 function-key immediately after the beep & before the Windows® start-screen & choose option 2.
These are "AT" [for attention] and "I" [for information] commands 1-7 sent to the modem by the computer. The response is the result sent back by the modem to each command sent. Any Terminal program can also be used to produce these results whilst NOT online.
Of particular importance are ati3, ati4, ati6 and ati7. Importance & result varies modem-to-modem, but generally ati6 gives clues to the modem chipset & ati3 gives the modem driver version. Please note that some manufacturers deliberately put non-informational responses into these information commands.
In What's My Modem? these responses are used to help identify the modem. Another way to obtain a print-out of these responses (Windows® only) is to use the program called mdu.exe. This was developed by & is copyright BVRP Software, & can also be sourced at modemhelp.com. It principally sucks info from the Registry but will also print out the ati responses if the com port is selected.
Errors with More Info...
Then the computer cannot communicate with the modem & at least a potential reason for not working has been discovered. A typical error message is
"The port is already open or in use..." Sometimes this can be fixed by shutting the computer down & switching back on again [don't ask, be happy].
It can also be caused by two sets of modem drivers, or other program, or other equipment, competing for the same port. If a program, this would normally be seen on the task bar or system tray in the task bar (the time also sits here) or not at all (silent running). Silent running programs are caught by giving the three-fingered salute (Ctrl+Alt+Delete) and waiting for 20 seconds (does not work with NT).
The program that most frequently gives rise to this message is RNAAPP (rnaapp.exe) and this is Dial Up Networking [DUN]. The question, of course, is what other program has caused DUN to be activated & then left in memory? Such programs may be started on system-boot (see also Q174018):
Finding Programs loaded at system boot
||<Windows> \Start Menu\Programs\StartUp
<Profiles> \Start Menu\Programs\StartUp
Errors with More Info...(cont.)
Gerry Kroll for the info on winstart.bat & the RunOnce section in the Registry
Graham Wood for the info on sysedit.exe
win95/8 provides sysedit
press Windows Start key
enter "sysedit" (no quotes)
win98 provides msconfig
press Windows Start key
enter "msconfig" (no quotes)
For further info, see
No wonder Windows is a hacker's paradise!
- Another symptom of errors is empty information in the responses to More Info.... At the very least this is indicating a Modem driver failure, & possibly a Modem hardware failure. Investigate Device Manager (a tab on the System Properties applet in Control Panel), though this result is indicating that the modem needs to be completely uninstalled, then reinstalled in the computer. That is, if it is still working - there (was) a test here to find out (Webmaster Note: not yet implemented).
Ctrl+Alt+Delete - the 3-fingered salute
Windows is notorious for system crashes and, with Win95/98, this is the almost-last-ditch solution to escape from such a crash. It brings up a list of the tasks (programs) running on the computer and gives options to end a specific task, shut the computer down or cancel the dialog. With winNT it is the means to log-on, which shows that some Windows®' programmer, somewhere, has a twisted sense of humour:
Depending on the state of your system it may take upto 20 seconds for this dialog to appear.
- hold down the Ctrl key on the left-side of the keyboard
- whilst you hold the first key down, press and hold down the Alt key
- whilst you hold the first two keys down, a single press of the Delete key
Windows® attempts to detect programs which are not responding to system-requests, and marks them as such in the task-list. If you End-Task such a program a second dialog will probably appear after yet another delay, and confirming this dialog will actually kill the program. DON'T KEEP WORKING! Windows® often suffers collateral damage from a dying program, so close all open programs and shut down/restart the computer.
There are two programs in the task-list which must not, ever, be closed down:
- Explorer - this is Windows Explorer
- Systray - this is the System Tray, where the time sits
It is also worth saying a few words about the way that Windows saves files. You may think that having pressed "Save" that that is the end of the matter - the last 4 hours of work is now safely on the disk. Hah! how innocent you are. Windows®
treats most such instructions as requests which it then completes in it's own good time (this does depend on the programmer). Memory is much faster to work in than from Hard-Disk and so, as far as possible, everything is kept in memory. The file in memory will be marked as closed and, when it has a quiet moment, Windows will write it to disk. This is why it is so important to go through the Windows®
Shut-Down procedure - all files in memory are closed and written to disk. It is also the reason that the 3-fingered-salute dialog contains a Shut-Down button - at least all files saved to date can be written to disc.
And finally, at the top of this little section it was said that the 3-fingered-salute is the "almost-last-ditch" solution to escape from a win95/98 system crash. The last-ditch solution is, of course, to switch off the power. If the paragraph above is re-read it will be realised why this is not recommended. If you have an ATX system even this will seem not to work! The power-button on these systems needs to be held in for 5 seconds before the power is cut. And don't worry - it fooled me the first time I came across it.