ReadString() get time limit exceed to complete operation error

Question

I have a device name Time Electronics 5075. I am trying to use the SimpleReadWrite.2010 in National Instruments\NI-488.2\Examples\DotNET4.0\SimpleReadWrite\cs to comunicate with the device.
I can open the connection and send commands to the device by using this code
device = new Device((int)boardIdNumericUpDown.Value,(byte)primaryAddressNumericUpDown.Value,(byte)currentSecondaryAddress);
device.IOTimeout = TimeoutValue.T100s;
device.Write("X0/A1/F0{13}");
 But I am stuck at 
stringReadTextBox.Text = device.ReadString();
I get the error "Time limit exceeded to complete operation."
I don't know exactly should I add 
device.Write("T/D{13}");
before the device.ReadString() or not. But I get the same error for both cases.
Some info: Visual Studio 2010, Measurement Studio 2013, NI.488.2, Windows 7 Pro
Any idea?

Answer 1

Thank you Curt_C,
I have attached the screen capture of NI IO Trace. I just open the session, send two commands T\n and D\n to the device and readstring. The red one are errors on reading. The last one is close session.
I think \n is the correct terminator. It works with most of commands, just get stuck with ReadString.
Kind regards,
Thang
PS: I also attached GPIB Interface Properties for more info
Attachments:
NI IO Trace_01.png ‏54 KB
GPIB Interface Properties.png ‏54 KB