PowerBase Issue: External Serial Device Detection

Power Computing provided the information in this article and it was deemed accurate as of 14 November 1997. Apple Computer, Inc. is not responsible for its content. This article is being provided as is and will not be updated in the future.

PowerBase customers with external serial devices, such as external modems, have reported problems working with the devices after system startup. This only happens prior to system 7.6.1.
PowerBase customers have reported problems where the computer is unable to detect an external serial device.

The majority of reported cases have been with external modems.

Symptoms:
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With external modems or other serial devices, the communications software can not detect the device. For instance, a modem will not respond with 'OK' to a simple 'AT' command. This problem occurs only if the device is powered off during system startup and then powered on after the desktop appears.


Workaround:
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* If you can, update to System 7.6.1 which resolved this issue.
* If you cannot upgrade to 7.6.1, simply power the device on before starting up the computer; which will allow the two to communicate.


Devices Affected:
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Customers have reported the issue usually affects external modems which are powered off of an external AC outlet. Modems which receive power either from the serial port or ADB port of the computer do not appear to be affected.

Issue Status:
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Power Computing has reproduced the problem on other MacOS computers from other manufactuers. All computers affected by the issue are based upon the 'Alchemy' architecture which is a logic board design licensed from Apple Computer.

Power Computing has escalated the issue to Apple Computer.

Machines Affected: Powerbase
Published Date: Feb 20, 2012