The TIMEOUT message into the stream viewer does indicate that no response was received by DataMiner from the device within the expected time. But the reasons of receiving a timeout message in the stream viewer can indeed be multiple:

1. The target device does not recognize the command that you are sending, and is therefore not transmitting any information back at all. In this case, it is recommended to check your command to see if that is completely corresponding to the documentation.
2. The target device does recognize the command that you are are sending, but is transmitting information back that does not fit within the response that you have configured.
3. The target device does recognize the command that you are sending but cannot reply within the timespan that you have set to receive an answer. This is by default 1500ms on an element, on a command basis.
4. The target device is unreachable, i.e. the IP cannot be reached, which is similar to a device not responding. It is again important to see if the timeout message only occurs to a single command, or if you have this on all commands.

My recommendations are:

1. Double-check the command that you are sending to exactly meet the documentation. If this is the only command on which you do not receive any response, this is a likely cause.
2. Double-check the IP address configured on the element to ensure you're targeting the correct device. Check IP connectivity also from the DataMiner Agent (RDP), not from your localhost.
3. Consult the DataMiner logs for this element (Apps -> System Center -> Logging -> Element -> Choose element). If required, increase the log level for this element to 'Log Everything'.
4. Increase the command timeout on your element from 1500 to a higher value to decrease the chances of the device not responding in time.
5. Open Wireshark program on the DataMiner Agent to check all bytes that are being sent over the network. This would also show if any information is sent out to the device, and whether or not the device is sending anything back.

These are my recommendations to start with. Typically once the first command does provide a response, you're on a good way. Communication with a device is a tricky thing, if it is not completely right, it is completely wrong :).