# Serial.client module giving Permission Denied exception

**URL:** <https://forum.inductiveautomation.com/t/serial-client-module-giving-permission-denied-exception/10463>\
**Category:** Ignition\
**Created:** [September 14, 2015, 8:41pm UTC](https://forum.inductiveautomation.com/t/serial-client-module-giving-permission-denied-exception/10463 "2015-09-14T20:41:24Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![JoeJansen](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/joejansen/32/5277_2.png) [@JoeJansen](https://forum.inductiveautomation.com/u/JoeJansen)\
**Post date:** [September 14, 2015, 8:41pm UTC](https://forum.inductiveautomation.com/t/serial-client-module-giving-permission-denied-exception/10463/1 "2015-09-14T20:41:24Z")

</div>

I’m trying to use the serial.client module to read data in from a barcode scanner. I’m running Ignition 7.7.5 on an ubuntu variant linux system.

I’ve used

```auto
cat /dev/ttyS0 
```

to verify the electrical connections and that I am using the right port. Scanning a barcode throws the data on the terminal screen.

I end the cat command, close the terminal, and launch my Ignition client. In the startup script I call a scripting function that does the configuration, then calls:

```auto
system.serial.openSerialPort("/dev/ttyS0")
```

I get a Java error from java.io.ioException stating that SerOpenPort failed: Permission denied.

I know I am addressing the port correctly, because when I forgot the leading / I was getting “No such device”.

What do I have to do to get the permissions correct to access /dev/ttyS0?

---

<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [September 14, 2015, 9:06pm UTC](https://forum.inductiveautomation.com/t/serial-client-module-giving-permission-denied-exception/10463/2 "2015-09-14T21:06:13Z")

</div>

You need to be running with root privileges or the user you’re running as needs to be a member of a certain group (on Ubuntu, I think the group is “dialout” by default… you’re on your own here though).