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Mac OS X Modem Update: Information and Download

This article has been archived and is no longer updated by Apple.

This article contains information about the Mac OS X Modem Update and a link to the software download.

The Mac OS X Modem Update resolves a rare issue in which a built-in modem cannot dial up. You may see the message "Internet Connect could not open the communications device".


After updating or installing Mac OS X 10.2, some Macintosh computers cannot dial out via their built-in modems. You may see these three symptoms: 

  1. Internet Connect gives this alert message when you attempt to dial up:
    "Internet Connect could not open the communications device."
  2. The Internet Connection Log contains this entry:
    "Failed to open /dev/cu.modem: Device busy."
  3. The modem works normally if you start up the computer from Mac OS 9.

Products affected

  • Mac OS X 10.2 to 10.2.1
  • Book (Late 2001)
  • iBook (14.1 LCD)
  • iBook (16 VRAM)
  • iBook (14.1 LCD 16 VRAM)
  • PowerBook G4 (Gigabit Ethernet)
  • PowerBook G4 (DVI)
  • iMac (Flat Panel)
  • iMac (Flat Panel 17)
  • eMac
  • PowerMac G4's: Dual 1GHz, Dual 1.25 GHz (Mirrored Drive Doors)
  • PowerBook G3 Series: 233, 250, 292 MHz (Wallstreet)


If you have not experienced the symptoms, you do not need to download the Mac OS X Modem Update.

If you access the Internet via your system's built-in modem, follow these steps below that require Mac OS 9 for downloading the update. Alternatively, if you do not have Mac OS 9 installed, you should download the update (as in Steps 3 and 4) from another location and then burn it on a CD to take back to your computer. If you live near an Apple Store retail location, you may get assistance there if necessary.

To download and install the Mac OS X Modem Update, follow these steps:

  1. If you have Mac OS 9 installed on the computer, start up the computer from Mac OS 9. For help, see How to Switch Between Mac OS 9 and Mac OS X.
  2. After the computer starts up, connect to the Internet. If you have not previously connected to the Internet in Mac OS 9, see Mac OS 9: How to Connect to the Internet via PPP (Dial-Up Access).
  3. Go to Apple Software Downloads (
  4. Search for "Mac OS X Modem Update".
  5. Download the update. If given the option to decompress the file after downloading it, click Cancel.
  6. Restart the computer from Mac OS X. For help doing this, see technical document How to Switch Between Mac OS 9 and Mac OS X.
  7. Open the Mac OS X Modem Update, and follow the directions.


The Mac OS X Modem Update license agreement permits the reproduction of software once for archival purposes only.

For help with downloading, see Software downloads: Formats and common error messages.

All software available from this site is covered by a software license agreement included with this software.

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