Any number of serial COM ports can be open simultaneously for data reception. To open a port, simply specify the BAUD rate desired by clicking on the drop-down box and selecting the desired baud rate from the list. To close a port, select (none) for the baud rate.
If the baud rate is not known, the auto-baud option will attempt to detect the incoming baud rate. This is performed by analysing the incoming data. If no data is received, the detection will fail.
Note: Some serial interface devices operate in a manner incompatible with the auto-detection routine. If the auto-detect remains inactive when data is input to the serial port, then the interface may be incompatible.
Ports that are not available to the program are not displayed in the list. Ports may not be available if they are not installed, or the Windows 95/98/NT driver is not installed, or is in use by another program.
Note that if a DOS application using a serial port has been run from a DOS window, and that window is still open, then the port may not be available, even though the application has terminated. Close the DOS window to free the port for Windows programs.
For linux, port numbers 1-64 are mapped to /dev/ttyS0 - /dev/ttyS63, and ports 65 onwards are mapped to /dev/ttyUSB0 onwards. Therefore USB connected serial ports will appear in the list having port numbers 65 onwards.
If the data links to the Acquisition computer are simplex (one direction only), the BRP protocol can cause more data to be lost than necessary. If a link is known to be simplex, the rewind feature of the serial driver should be disabled. This is done by clearing the ‘BRP’ check box.
Scream incorporates an auto-baud feature which allows dynamic re-training of a changed (or unknown) input baud rate. Whilst the triggering of the auto-baud detection should never occur during normal operation, some conditions can cause a false tripping of the procedure (e.g. poor quality radio link). If this is a problem, auto-baud can be disabled by clearing the ‘AutoBaud’ box.
If a modem is detected on the serial port, the dialup is enabled.
See Also: Setup, Automatic Dialup