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  3. Modem question (again)

Modem question (again)

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  • B Offline
    B Offline
    Black Cat
    wrote on last edited by
    #1

    I bought and installed a new serial modem (56k, external). It works great. The first time I used it to connect to AOL, AOL said the connection speed was 115200!!! It was super fast that day or may be it's just my illusion. Unfortunately, it never happened again. Now the connection speed is always under 56k. I am not a hardware person at all. Can anyone explain what is going on? Thanks.

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    • B Black Cat

      I bought and installed a new serial modem (56k, external). It works great. The first time I used it to connect to AOL, AOL said the connection speed was 115200!!! It was super fast that day or may be it's just my illusion. Unfortunately, it never happened again. Now the connection speed is always under 56k. I am not a hardware person at all. Can anyone explain what is going on? Thanks.

      S Offline
      S Offline
      Stefan Spenz
      wrote on last edited by
      #2

      The real connection speed depends on the "quality" of the connect you get, usually its somewhat between 46k-48k. Maybe, when you used your modem first time, no proper driver was installed or Win took the standard modem driver to operate the modem. On some of them there are wrong connections speeds assuming the modem is running at 115k, while truly running at 46k.

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      • B Black Cat

        I bought and installed a new serial modem (56k, external). It works great. The first time I used it to connect to AOL, AOL said the connection speed was 115200!!! It was super fast that day or may be it's just my illusion. Unfortunately, it never happened again. Now the connection speed is always under 56k. I am not a hardware person at all. Can anyone explain what is going on? Thanks.

        C Offline
        C Offline
        Chris Losinger
        wrote on last edited by
        #3

        i always assumed that 115K was the speed the COM port was talking to the modem itself. -c


        Cheap Oil. It's worth it!

        Image Processing?

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        • B Black Cat

          I bought and installed a new serial modem (56k, external). It works great. The first time I used it to connect to AOL, AOL said the connection speed was 115200!!! It was super fast that day or may be it's just my illusion. Unfortunately, it never happened again. Now the connection speed is always under 56k. I am not a hardware person at all. Can anyone explain what is going on? Thanks.

          R Offline
          R Offline
          Roger Wright
          wrote on last edited by
          #4

          There are two speeds involved in using a modem. One is the line speed between modems, the other is the port speed between your PC's serial port and your modem. The top speed for a serial port based on the 16550 UART (most common in PCs) is 115200, which the AOL software reported initially. Depending on the program implementation, it may be adjusting the local port speed to match the line speed. The PC has no way to actually sense the real line speed - it must rely on the modem to tell it via the CONNECT XXXX message when a connection is established, or calculate the effective speed on the fly. Any time you're in doubt, though, set the local port speed higher than the expected line speed to reduce the chance of missed data. If you want to get more info, look at the MSComm control in the VB documentation. I think there's an equivalent in VC++, but I've never located it... Let's Put The Fun Back In Dysfunctional! - My Darts Team T-shirt

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