TITLE
    Modem Initialization Strings
Article ID:
Created:
Modified: 		24708
11/4/98
4/7/00
TOPIC

    This article contains the initialization string for the iMac's internal 56K modem.

    Note: The modem used in the iMac and the Power Macintosh G3 (Blue and White) are similar, thus the information provided in this article is relevant to the Power Macintosh G3 (Blue and White) also.

DISCUSSION

    The iMac modem init string is embedded in the modem script (CCL) that is stored in the Modem Scripts folder located in the Extensions Folder. These files can be inspected using a text editing application.

    NOTE: Apple does not provide support for CCL file editing or support the use of any CCL's other than those included in the Mac OS.

    The initialization strings that have been provided for the iMac modem scripts are as follows:

    iMac Internal 56K:
    AT&FE0Q0V1X4&C1&K3S95=1S7=75S0=0\13

    iMac Internal 56K (v.34 Only):
    AT&FE0Q0V1X4&C1&K3S95=1S7=75S0=0+MS=11\13

    But these strings can be condensed even further.

    Broken apart, we have "AT &F E0 Q0 V1 X4 &C1 &K3 S95=1 S7=75 S0=0 \13"

    Given that a number of these items are there for use within the CCL, they are not typically required for basic initialization of the modem.

    Q0, V1, X4, &C1, &K3 and S0=0 are default settings for the modem.

    These additional settings are used in the interface coding guidelines for the CCL so as to provide error checking
    redundancy during initialization.

    If a register setting fails to initialize properly during this process, the CCL has additional logical statements that will provide feedback to the application that is dialing the modem.

    So in removing them, we get: AT &F E0 S95=1 S7=75 \13

    While E0 disables echo in command mode, whether it remains here will be largely dependent upon whether the particular dialing program can make use of it. It is typically not required, so we remove it. The \13 is for nothing more that a carriage return, to instruct the program to interpret the line. This with be handled by the dialing program, so is not required.

    So now we have: AT&FS95=1S7=75

    Finally, the W2 command implements connection rates for the connection. Other connection information that is defined by the "S95=1" is hardly ever used and can also be removed. So with the substitution of W2 for S95=1,

    we get: AT&FW2S7=75

    and, for V.34: AT&FW2S7=75+MS=11

    For more information on AT commands, see the document "AT Commands.pdf," located in the Internal Modem folder in the Apple Extras folder on you hard drive.

    You can also download the AT Commands PDF document. To download a pdf of the AT Command set, go to the Apple Manuals Web site query screen at http://www.info.apple.com/manuals/manuals.qry . Enter AT Command as your search string to locate then download the pdf document.

Document Information
Product Area: Computers; iMac
Category: Power Macintosh; iMac Software
Sub Category: Power Macintosh G3 - Blue and White; Communications; Troubleshooting

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