# Re: RuntimeError: b200: 2 RX 1 TX and 1 RX 2 TX configurations not possible

**URL:** <https://www.ruby-forum.com/t/re-runtimeerror-b200-2-rx-1-tx-and-1-rx-2-tx-configurations-not-possible/233104>\
**Category:** GNU Radio\
**Created:** [November 18, 2014, 3:05am UTC](https://www.ruby-forum.com/t/re-runtimeerror-b200-2-rx-1-tx-and-1-rx-2-tx-configurations-not-possible/233104 "2014-11-18T03:05:00Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [November 18, 2014, 3:05am UTC](https://www.ruby-forum.com/t/re-runtimeerror-b200-2-rx-1-tx-and-1-rx-2-tx-configurations-not-possible/233104/1 "2014-11-18T03:05:00Z")

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Hi Lefteris

thank you for bringing that up!

There has indeed been a bug in UHD caused by parallel access to rx/tx  
methods by gnuradio.  
Please find a patch attached that will fix the issue for the time being.  
This code is not yet finalized but should solve your problem.

Cheers,  
Julian