# Re: USRP drivers vs UHD drivers in gnuradio-companion

**URL:** <https://www.ruby-forum.com/t/re-usrp-drivers-vs-uhd-drivers-in-gnuradio-companion/202289>\
**Category:** GNU Radio\
**Created:** [January 26, 2011, 4:31am UTC](https://www.ruby-forum.com/t/re-usrp-drivers-vs-uhd-drivers-in-gnuradio-companion/202289 "2011-01-26T04:31:20Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![dubstep](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/cdc98d/32.png) [@dubstep](https://www.ruby-forum.com/u/dubstep)\
**Post date:** [January 26, 2011, 4:31am UTC](https://www.ruby-forum.com/t/re-usrp-drivers-vs-uhd-drivers-in-gnuradio-companion/202289/1 "2011-01-26T04:31:20Z")

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> > Also, it used to be that I needed to be in the “usrp” group in order to access  
> > the USRP.
> 
> > Now i deleted this group and i still have access to usrp (even when the source  
> > is not a uhd one but a usrp source)!
> 
> > My understanding is that if i use the uhd device then i can do that  
> > (ie, don’t need to be in the “usrp” group) but it seems to be happening even  
> > with the usrp source.
> 
> > What am I missing?

> Merely deleting the “usrp” group from group file doesn’t do anything until you  
> log-out/log-in again.

yes I did logout/login (even rebooted the system to make sure)…

Achilleas

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**Author:** ![Achilleas\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/74df32/32.png) [@Achilleas\_A](https://www.ruby-forum.com/u/Achilleas_A)\
**Post date:** [January 26, 2011, 4:41am UTC](https://www.ruby-forum.com/t/re-usrp-drivers-vs-uhd-drivers-in-gnuradio-companion/202289/2 "2011-01-26T04:41:58Z")

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On 01/25/2011 10:30 PM, Achilleas A. wrote:

> yes I did logout/login (even rebooted the system to make sure)…

Well, in that case, probably your “UDEV” rules create the device world  
read/write.

Check /etc/udev/rules.d/\*usrp.rules

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**Author:** ![Achilleas\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/74df32/32.png) [@Achilleas\_A](https://www.ruby-forum.com/u/Achilleas_A)\
**Post date:** [January 26, 2011, 4:43am UTC](https://www.ruby-forum.com/t/re-usrp-drivers-vs-uhd-drivers-in-gnuradio-companion/202289/3 "2011-01-26T04:43:13Z")

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On 01/25/2011 07:30 PM, Achilleas A. wrote:

> > > Also, it used to be that I needed to be in the “usrp” group in order to access  
> > > the USRP.  
> > > Now i deleted this group and i still have access to usrp (even when the source  
> > > is not a uhd one but a usrp source)!  
> > > My understanding is that if i use the uhd device then i can do that  
> > > (ie, don’t need to be in the “usrp” group) but it seems to be happening even  
> > > with the usrp source.  
> > > What am I missing?

It depends on your udev settings:  
[http://www.ettus.com/uhd\_docs/manual/html/usrp1.html#linux-setup-udev](http://www.ettus.com/uhd_docs/manual/html/usrp1.html#linux-setup-udev)

The udev instructions I put in the UHD manual set the device wide open  
to anyone on the system.

-Josh