Read serial input from /dev/tty in linux

I'm trying to visualize the input of a serial device. The device lies in "/dev/ttyACM0". I already found out, that MATLAB doesn't read this kind of device, so I made a link to it called "/dev/ttyS101". I can perfectly read the output of the device using "cat" in the console, but if I try using fopen() in MATLAB I always get this response:

Error using serial/fopen (line 72)
Open failed: Port: ttyS101 is not available. No ports are
available.
Use INSTRFIND to determine if other instrument objects are
connected to the requested device.

I don't have the "Instrument Control Toolbox" installed, is that the problem?

Answer 1

[Walter Roberson]

instrfind() is part of MATLAB these days.

Check the ownership and permissions on /dev/ttyS101 . It would not be uncommon for it to have been configured without "other" access.

[Christian Wittpahl]

You were half right! the ownership of /dev/ttyS101 was alright, but the /var/lock folder was owned by root, while matlab was trying to create a file/folder there.