Bi-directional serial data flow

I’m new at this so please bear with me…

I have a serial device that I want to be able to access over Ethernet. The device both sends and receives data serially.

The problem I’m having is that I can receive data from it over the network (using the Digi EM and a HyperTerminal window (configured for TCP/IP winsock)), but I can’t send data to it from the same HyperTerminal window. I can do this using the PC’s local serial port and HyperTerminal (configured for COMx). I was hoping the Digi EM would essentially allow me to interact with the serial device as if it were connected to the local COM port, but do so over the network. Is this possible, and if so, what must I do to make it work?

Thanks for professional expertise.


How do you know you’re recieving data (i.e. you can see a menu or something of the like pop up)? How do you know the remote device isn’t recieving the data you type (i.e. if you hit a character does it browse through the menu)? In the EM/Wi-EM’s Web UI you can check the serial port statistics (Web UI -> System Information -> Serial -> Port x) and see if data sent and recieved is incrementing as you type or recieve information. If it is, you know data is being sent to the device. After that, it’s likely that there’s some type of unexpected flow control going on (i.e. you need to configure the serial port for no, software, or hardware to match the attached serial device), configuring the serial settings can be found under Serial Ports -> Port x -> Basic Serial Settings.

When the serial device is reset it automatically transmits a menu over the serial bus. I’m able to see this menu in HyperTerminal. However nothing happens when attempting to interact with the menu.

Now the good news… I didn’t know I could monitor the bytes sent/received using System Information, so I’m greatful to you for mentioning that.

It turns out that I was connecting the EM’s transmit line to the receive line of a microcontroller. All well & good except there was a max232 level shifter also connected to the controller’s receive line. Esentially the level shifter was holding the EM’s transmit line high inhibiting all receive data (newbie, remember?). Once the max232 was removed, all was fine.

Thanks for your input because I learned about features I may not have otherwise found out about, and sorry for bothering the group before finishing my homework.