VI_ERROR_TMO (-1073807339) on Anritsu OSA

Question

I'm working on interfacing an old Optical Spectrum Analyzer Anritsu MS9710B with a RS232 connection. A year ago, I managed to comunicate with him, send SCPI command using pyvisa and receive data. Today, I execute the exact same code with libraries up to date and I get an error Timeout when I query IDN or anything. The RS232-USB drivers are ok, I manage to open a communication but a query or read fail.

I changed the parameter to "RS232C" on the OSA parameters and my communication parameters are the same between OSA and program. Following advices from the forum, I tried the connection with NI-VISA where I get the same error. I tried to change timeout parameter, write_termination and read_termination but there isn't any change. The manual is very hard to understand termination value, but when it worked I didn't add anything.

I don't know anymore what to do.

Any advices and help would be warmly welcome to fix my problem !

import pyvisa
from pyvisa.constants import StopBits, Parity



rm = pyvisa.ResourceManager()
print(rm.list_resources())
my_instrument = rm.open_resource('ASRL5::INSTR')
my_instrument.baud_rate=9600
my_instrument.data_bits=8
my_instrument.parity=Parity.even
my_instrument.stop_bits=StopBits.one


my_instrument.write('*IDN?')
print(my_instrument.read())```

'''
('ASRL5::INSTR',)
Traceback (most recent call last):
  File "PremiereComm.py", line 26, in <module>
    print(my_instrument.read())
  File "C:\Program Files\Python38\lib\site-packages\pyvisa\resources\messagebased.py", line 486, in read
    message = self._read_raw().decode(enco)
  File "C:\Program Files\Python38\lib\site-packages\pyvisa\resources\messagebased.py", line 442, in _read_raw
    chunk, status = self.visalib.read(self.session, size)
  File "C:\Program Files\Python38\lib\site-packages\pyvisa\ctwrapper\functions.py", line 2337, in read
    ret = library.viRead(session, buffer, count, byref(return_count))
  File "C:\Program Files\Python38\lib\site-packages\pyvisa\ctwrapper\highlevel.py", line 222, in _return_handler
    return self.handle_return_value(session, ret_value)  # type: ignore
  File "C:\Program Files\Python38\lib\site-packages\pyvisa\highlevel.py", line 251, in handle_return_value
    raise errors.VisaIOError(rv)
pyvisa.errors.VisaIOError: VI_ERROR_TMO (-1073807339): Timeout expired before operation completed.
>>> '''