UNSOLVED
Unable to open COM2
My system is a Dimesion 4100 866Mhz w/ 512 mb of RAM and a US robotics 56K voice PCI modem (supplied by Dell at purchase.) The modem says it is using COM5.
The modem runs slower (30,000-42,000) than my Dell xps200 (42,000-48,000) when using the same phone line. I switched the phone line from one modem to the other to test. For this test I used a line direct from the modem to the wall jack. Before I re-arranged my office the 4100 always ran at 42-48,000 and I didn't change any of the wiring.
I started to troubleshoot the problem and one of the first things to check was the phone line, so I tried that notwithstanding the above test results.
Using Doc. no. TT1012530 I opened Hyperterminal, created "test.ht" and set it to "Direct on COM2". When I clicked OK I got: "Unable to open COM2. Please check your port settings."
Using directions in Hyperterminal Help I opened test.ht properties, selected the "Connect to" tab and clicked on "Configure". Nothing happened. I tried several times.
Any clues about COM2 or why one system runs slower than the other will be appreciated.
- Why are you trying to connect on COM2 when you said the modem was installed on COM5? (most likely there is no COM2 on your system).
If I remmber right, Hyperterm may not offer COM5. The normal installation of a USR/3COM modem installs the modem on COM5, but also creates a Com alias on COM3. Try connecting there. I was using COM2 because that's what the instructions in TT1012530 called for. I just assumed whoever wrote that knew what was right. I think when I looked in the BIOS there was only COM1, which should have been a clue I guess.
Is there a reason that only one com port would be listed in the BIOS? Where can I go to learn more about the port arrangements?
- A COM port designation is really just a historical combination of base address and IRQ. The serial port on the back of your machine is configured to use the historical address IRQ definition of COM1. COM1 is the only real COM port the machine has, so that is all that is listed in the BIOS.
Many of the USR/3COM modems install themselves using a base address and IRQ that have historically been considered as COM5. In reality, it is not a true COM port, but simply a combination of address/IRQ. For legacy purposes (many older programs only recognize the address/IRQ combos that define Com1-4) the modem also installs an entry in the registry that redirects to the COM5 address/IRQ I/O directed at COM3.
I don't claim the above is totally technically correct or is the whole story, but I think it helps get the idea across.
fredopatz
4 Posts
1311
0
Posted November 5th, 2003 12:00