fopen() error with serial device

Hi,

under Linux we'd like to send a text string to a serial device:

% --- code ---> >> s = serial('/dev/ttyS0');

% a serial object s is returned

>> set(s,'BaudRate',19200); % adjust the baudrate

>> fopen(s)

Error using serial/fopen (line 72) Open failed: Port: /dev/ttyS0 is not available. No ports are available. Use INSTRFIND to determine if other instrument objects are connected to the requested device.

% the serial device is still there

>> instrfind

   Serial Port Object : Serial-/dev/ttyS0

   Communication Settings 
      Port:               /dev/ttyS0
      BaudRate:           19200
      Terminator:         'LF'

   Communication State 
      Status:             closed
      RecordStatus:       off

   Read/Write State  
      TransferStatus:     idle
      BytesAvailable:     0
      ValuesReceived:     0
      ValuesSent:         0

% --- code ---<

Are there special toolboxes neccessary to connect to a serial device?

Regards, Roger

[2000rogers]

It occurs to be a group-rights related problem since the device is root/dialout

sudo usermod -a -G dialout myuser

cures the problem.

Regards, Roger