Modem problem

Compudyne (compusa house brand) UNKNOWN
January 29, 2009 at 13:42:44
Specs: Dos6.2/Win31,Win95,WinME,XP, 486 DX 50
I was given a 486DX50 that is in excellent condition. It runs Win31 but I am having some problems with the modem. I have it connected to a phone line and am sure that the phone line is live, cause I connected a phone to the Fax/Modem card and got a dial tone and was able to make a call from the phone. My software (AOL and Fax) says that it can not detect the modem. I don't know what kind of modem it is, I suspect US Robotics (but not sure) I was finally able to find the Bios sequence to enable me to diable the COM1 serial port. This initially allowed the fax software to recognize it, but that didn't last long. From what I can see, the Fax/Modem card is still working, or I wouldn't be able to get a dial tone. Right?
I don't see any IRQ conflicts as it is connected to #4. Any suggestions would be appreciated.

ghro


See More: Modem problem

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#1
January 29, 2009 at 14:05:19
I've never used Windows 3.1 but generally, any operating system I've had needed specific drivers for the hardware that was connected.
You will need to identify the exact model modem and try to find appropriate drivers for your operating system. There is a Win 3.1 forum where you might like to seek answers

Goin' Fishin' (Some day)


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#2
January 29, 2009 at 14:09:57
I believe Win3.1 needs a hardwarw modem not a Win9x type software modem. The software type modems require drivers. Check to model of the modem.

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#3
January 29, 2009 at 16:24:43
Shutdown Win3.1 on the machine and from plain DOS run MSD.EXE and see if the serial port for the modem shows up. In other words, if you used the BIOS configuration to disable the onboard COM1 on the motherboard, and have the modem set up as COM1 (IRQ4, 3F8H), then MSD.EXE should show a COM1 with the correct IRQ and address. If it doesn't, then that's your problem. If it does, then turn off the computer and physically remove the modem. Then restart the computer and check if MSD still sees a COM1 (at this time carefully study the modem and see if you can determine it's make and model). If MSD shows that there is no COM1 with the modem removed, then replace the modem. You now know that the modem is good at the hardware level. With the information you got from taking a close look at the modem, see if you can find configuration and driver information about it on the Internet. Oh, if MSD.EXE DOESN'T see a COM port for the modem, then either the modem is broke, misconfigured, or is a software modem which will require a special Windows 3.1 driver to make it work.


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Related Solutions

#4
January 29, 2009 at 19:15:26
Thanks everyone I will try to detemine the make/model of the modem. I will have to open it up after checking with MSD. I have already added a 5.25 floppy to the system. On another issue, there is a set of 8 jumper switches on the back of the computer, with 3,5 and 8 set to the 'on' position. I've never seen this before. I have heard that some IRQ's are set with jumper switches, but why would some be set to the off position when other systems will need that setting to be on. I don't believe these are IRQ's though for that reason. Without documentation it's hard to know except by trial and error.


ghro


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#5
January 29, 2009 at 20:30:33
This is what I found when checking MSD:
Class 1 Fax/Modem
Port Address 02F28H
Baud Rate 2400
Parity N
Data Bits 8
Stop Bits 1
Carrier Detect No
Ring Indicator No
Data Set Ready Yes
Clear to Send Yes
UART Chip Used 16550AF

I changed the baud rate to different settings and restarted the computer several times, the above info is what was recognized. AOL {v3) detected a New Media 14.4 PCMCIA at setup, but when this was tried it failed to sign on. The port was changed in the control panel and system restarted, but MSD did not recognize this so it was changed back to 2400. I guess I will have to open it up to hopefully find Make/Model info. I'll keep you posted

ghro


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#6
January 30, 2009 at 12:13:41
The port address 02f8h is for COM2 (IRQ3). If you have it trying to use IRQ4 with that address, it won't work. Here are the COM Port "rules" for PCs:

COM1....IRQ4/03F8h
COM2....IRQ3/02F8h
COM3....IRQ4/03E8h
COM4....IRQ3/02E8h

It is best to avoid trying to use COM3 and COM4, a lot of software/hardware really doesn't support it. But, if you "tell" a piece of software to use the modem at COM1, it will look at IRQ4/03F8h and if no modem responds (which it won't if it's set on address 02F8h) then the software won't "find" the modem. Your computer's mainboard also has built-in UARTs. If they are enabled and assigned the same address or IRQ as the UART on your modem, they will block software from finding the modem's UART. The 16550AF is a high speed UART and should be able to work up to 115200bps (or baud), typically a modem's UART speed will be set by the firmware's negotiation with another modem, the BAUD you set will be the MAX speed it will use.

The jumper switches on the back of the computer are unique to that make/model of computer. Don't mess with them until you find a manual/description of what each switch does. It's possible that some of them have something to do with IRQs, but they are just as likely to have something to do with processor type, memory, math coprocessor, etc.


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#7
January 30, 2009 at 12:31:11
Pyrolitic:
Thanks for the info. I'll take a look at the fax/modem card to see if I can get some additonal information.

ghro


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#8
January 30, 2009 at 12:48:52
I'm coming in at the end here but I will say two things.

First, good info in #6.

Second, that has to be an add in card so any jumpers that relate to the modem will be ON the modem, not elsewhere. Any jumpers and/or dip switches on the motherboard relate to processor speed and/or voltages. Messing with them can kill the CPU.

There was NO IRQ sharing in Win3.1 so you have to use a unique IRQ for each piece of hardware.


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#9
January 30, 2009 at 16:41:37
OtheHill
Not a problem, the more info the better. I'll leave them alone, why kill a good machine. I've been looking on the Net to see if I could find some documentation. Nothing yet though. I will take a look at the fax/modem card for some info and get back to you. Thanks again.

ghro


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#10
January 31, 2009 at 14:07:29
Just in case you don't find any good info on the modem, since it is already set up on COM2 (this was kind of a "default" for modems back in the day of 486DX50 computers because COM1 was usually used for the mouse), then just disable any COM2 port on the computer, make sure there's no conflicts with IRQ3, and use it on COM2. If your software has the option to identify the modem, just experiment with what's available. "Hays" or "Hays compatible" is a good generic choice to start with.


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#11
January 31, 2009 at 15:27:53
Yea, Hayes or US Robotics were the two big names.

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#12
February 1, 2009 at 05:47:33
I opened it up yesterday morning and found some infomation. The PC is a Compudyne pt66w. I found a picture of it when searching the Net at this address http://baza.farpost.ru/4304438.html. Looks like its up for sale on a russian site, but thats it except for a few differences. Notice no jumper switches cause after looking at it again, those switches are actually on the modem which is a US Robotics Sportster Model 0266. I checked for the driver information in W31 and don't see anything so I will look on the Net to see what's out there.

ghro


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