How to load .dat files to oracle database
Not all .dat files are the same and it's hard to determine from the screenshot what the format is.

If you extracted that from a telecom switch, you will need to contact the telecom vendor to ask if they have a data provider for the file format and use that provider to make a connection to the .dat file from within your ETL tools.

If they don't have a provider, which is entirely plausible, you will need to extract the data in another format such as .csv. Again, contact the vendor to see if that is an option