Error: Communications error on COMn (***O***)

Problem:

This is a low level error in the hardware layer that is reported to the server from the Microsoft Comm. library, or equivalent library. The error is a Character buffer over run.

Solution:

This error is more likely to be seen on NT4.0 machines but can be seen on newer operation systems which are communicating to legacy serial hardware. Typically if seen it is when talking to serial devices at a baud rate 19200.