Knowledge Base

Reconnecting Through the Serial Port Hangs Pentium Computers

Article ID: 114767

Article Last Modified on 10/31/2006

APPLIES TO

This article was previously published under Q114767

SYMPTOMS

On a Pentium-based computer, when you start a serial communications program, make a connection, exit the communications program, restart the communications program and attempt to make a connection again, Windows NT stops responding (hangs), requiring a hardware reset.

CAUSE

When SERIAL.SYS attempts to simultaneously put the 16550 UART serial port controller into FIFO mode and clear the data in the receive buffer when it already is in FIFO mode and has data in the buffer, the LSR incorrectly continues to think that there is data in the receive buffer even after you read the data register. This hangs the computer at the hardware level.

STATUS

Microsoft has confirmed this to be a problem in Windows NT and Windows NT Advanced Server version 3.1. This problem has been corrected in the latest U.S. Service Pack for Windows NT and Windows NT Advanced Server version 3.1. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K


Additional query words: prodnt modem freeze

Keywords: kbother KB114767


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