I have a Fiscal Thermal Printer Epson FP-260SV GPRS connected to PC with RS232 cable (or a USB to serial port adapter).

I have a Fiscal Thermal Printer Epson FP-260SV GPRS connected to PC with RS232 cable (or a USB to serial port adapter).
How to print to that printer directly to COM port?
I've been using the simple code but nothing prints out:

try
AssignFile(prnfile, aFile);
Reset(prnfile);
AssignFile(port, 'COM4');
Rewrite(port);
while not eof(prnfile) do
begin
Readln(prnfile, buffer);
Writeln(port, buffer);
end;
finally
CloseFile(port);
CloseFile(prnfile);
end;