I have problem in the send my background file to my range so its no available to send
I don't think Terrasync supports the DXF format as a background file. ESRI shape files are supported, so if possible try them instead.
As James states, the *.dxf file format is not supported in Terrasync (but is supported in GPS Pathfinder Office)
To get this file into Terrasync you will need to import this into GPS Pathfinder office first which converts this to a native *.imp format. You can then transfer the file to Terrasync via Data Transfer as a background file
The process summary is as follows:
TerraSync software supports the following background map formats
Retrieving data ...