Description:
Use this method to open the port. Returns an ID used for the 
 communicating MAC functions.
if ID is 0 the port could not be opened. Use MAC_GetLastErr to 
 se what coursed the error.
Factors are set to default every time this function is called.

Author    : Rune Rafn (Quickwood Automation) 8/1-2004
Supported : Target from version 0.0.0.10 and later.

Parameters:
Input:
COMPORT : Comport to open.
 
Output: 
 ID 	: ID for comport. Used to other communicating MAC functions