2127 DataSpanner application "lock-up" or  "hang"

The MS-Windows FIFO Buffers for your serial (COM) port are set above the minimum setting. If MS-Windows receives a packet that does NOT fill this buffer, it will WAIT until the buffer is full.  If, for example, the last packet received by the MS-Windows buffer is too small AND the last responding packet from the NCR 2127 does NOT fill this buffer, MS-Windows will NOT release the buffered data and the Vesper Software application will not receive confirmation that the NCR 2127 has responded or completed its action. The result appears that the system has "hung" or "locked-up". SOLUTION: Set the serial port buffers to their lowest settings. 

1. From the Start-Settings-Control Panel-System
2. Device Manager 
3. Select Ports
4. Select COM port used by the 2127 DataSpanner
5. Port Settings tab
6. Advanced button
7. Change all buffer settings to lowest position 
8. Select OK