3CCM756 56K WinModem PC Card and 3CXM756 56K WinModem PC Card with XJack Connector

3CXM756, 3CCM756

  • Modem returns a "No Dialtone" error message.
  • Will my PC Card function properly outside of North America?
  • New modem problems with Dial Up Networking.
  • PC Card trouble with Motorola Startac 7790 Phone.
  • PCMCIA modem and Gateway Solo 9100 running Windows NT 4.0.
  • Modem problems with NEC 6000 series laptop running Windows NT 4.0.
  • Technical Bulletins

  • Configure Your PC Card With Modem Initialization Strings
  • Connect Your Compatible Cellular Cable
  • Configure Windows 9x For Internet Services
  • Acquire Firmware Upgrade From Our Web Site
  • Verify Your PC Card Controller Is Configured For Windows 9x
  • Determine Product and Firmware Revision
  • Configure Your System For PC Card Modems In Windows 9x

    Additional Support

    If the support information in this section doesn't help you solve your issue, you can contact a USR Help Desk Technician directly.

    Manuals and other Documents
    None available at this time


    OS Compatibility


    2012 R2







    Vista 64


    XP 64




    98 SE

    98 FE





    Drivers and Firmware
    The 3Cxx356 is not supported within Windows XP. We recommend model 3Cxx756 for use with Windows XP. Visit our product page for detailed information on this and all of our products.
    Updated Windows 2000 drivers
    356W2K.exe 712 KB 11-29-00
    Windows 9x installation files
    This file contains the install disk for the 3Com/Megahertz 3cxm356 and 3ccm356 modem. NOTE: This install is for Windows 95 and Windows 98 ONLY! If you need drivers for NT 4.0, please refer to the file 356NT.EXE.
    3cxm356.exe1 MB 05-06-99
    Windows NT 4.0 installation files
    This file contains the install disk for the 3Com/Megahertz 3cxm356 and 3ccm356 modem. NOTE: This install is for Windows NT 4.0 ONLY! If you need an install disk for Windows 95 or Windows 98, please refer to the file 3CXM356.EXE.
    356nt.exe770 KB 05-05-99

    Cut the Cord and Go Cellular! Cellular Gateway Cellular Modems and Gateways make the M2M world go round. Learn all about Cellular

    Network TAPs Aggregation Tap Get your SPAN ports back and truly see into your network traffic. Start Tapping now!

    Share Telephone Lines Call Director Line Sharing Device Learn how you can save money by letting your modem, POS, fax and telephone all share one line. Learn more now!

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    Warranty Service Learn how to send your product in for warranty service.

    Electronic product documentation is provided as a courtesy to USRobotics customers. These are electronic versions of the original documentation. Some of the information contained within this documentation, including the support contact information, is subject to change.