If the .ent file has only CR at the end of each line (no LF),
then set your terminal emulator to delay 100ms after the end
of each line. The .ent file can then be sent at 9600 baud.
Otherwise, the transfer will have to take place at 1200 baud.

If you're using TeraTerm as your terminal emulator, then it
will remove the LF character from any .ent file you send if
you UNCHECK the Binary option in the File->Send_File... dialog.

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If you aren't using TeraTerm, you can easily remove the LF from
.ent files using the hex2ent utility. For example, the command
"hex2ent program.ent" creates the output file "program-NOLF.ent"
that is program.ent with only a CR at the end of each line. 

Of course, the hex2ent utility also converts Intel hex files
into .ent files. The .ent file created has only a CR at the end
of each line.

Find the hex2ent utility here:
https://deramp.com/downloads/processor_technology/sol-20/software/hex_to_ent_converter/