How can you clear a hung (stuck) port?

Cause:

If the ON LED goes out, this means the unit is corrupt.  

Solution:

If you have a port that doesn't seem to work, try simply moving the cable from the failing port to an unused port, changing the application to point to the new port and see if operations can be resumed.  If not, then it's not the port, it's the device.  If the device fails:
1. Verify you are running the latest EtherLite driver.
2. Verify socket 771, which the RealPort driver uses to talk to the EtherLite is not blocked on the network.
3. Try running Verlog.exe.  This utility can be downloaded from:http://supportold.digi.com/support/utilities/sts_els/.  
     Run Verlog.exe and enter the IP Address of the EtherLite to verify that the EtherLite is responsive.  If so, try 
    reinstalling the driver.
4. If not, try running BootPS.exe.  This utility can be downloaded from:http://supportold.digi.com/support/utilities/sts_els/.
5. Run BootPS.exe and power cycle the EtherLite.  You should get a response from the EtherLite's MAC address and IP 
    Address.  If you don't get a response, verify your network connectivity and EtherLite LEDs.  

If it is the port, try rebooting and see if the port returns on reboot.  If so, the port probably got jammed.  If it happens with any regularity, contact Tech Support to see if the problem can be diagnosed.  If the port never comes back, then likely, the RS-232 line driver(s) and/or receiver(s) have been damaged by something environmental, and the unit needs to be returned for repair.

If the port comes back at every boot, but seems to jam permanently on first access, you probably have a simple case of flow control, cabling, or configuration problem.

Flow Control:

• Hardware flow control uses pins RTS and CTS to gate flow back and forth between two connected serial devices. The DTE device uses RTS to start and stop flow from the DCE device, and the DCE device uses CTS to gate flow from the DTE device.

  This method is popular for higher speed connections where flow control reaction time is more critical. It's also popular where the data stream is such that embedded flow control characters can not be tolerated by the protocol running on the link. The cost is that you have to run two more wires in the cable.

   

• Software flow control uses special START (XON) and STOP (XOFF) characters embedded in the data stream to gate flow. In other words, the receiving device would send a STOP character (typically a control-s) to the sending device to halt flow. It would then later send a START character (typically a control-q) to resume flow.

  This method of flow control is more popular for slower links whose protocol can support embedded flow control characters. It's popular because it only requires that you run 3 wires for the link to function. Receive (RxD), Transmit (TxD), and Ground (GND).