Re: Configuration of the RGA200 communication baud rate

[Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>]

Hi Eric,

I have an RHEL 9 system.  How do I set an arbitrary baud rate using termios2 from the shell?  When I use stty I get an error:

[epics@13idd ~]$ stty -F /dev/ttyUSB0 28800

stty: invalid argument ‘28800’

Try 'stty --help' for more information.

Thanks,

Mark

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Eric Norum via Tech-talk <tech-talk at aps.anl.gov>
Sent: Monday, January 12, 2026 11:20 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: Configuration of the RGA200 communication baud rate

 

What platform is this?  The error message implies that your system is not providing a definition for B28800.

Perhaps drvAsynSerialPort.c should be modified to use termios2 where it exists.

On Jan 11, 2026, at 9:29 PM, LONG FENG via Tech-talk <tech-talk at aps.anl.gov> wrote:

Hi all,

We encountered an issue while configuring the communication baud rate for the RGA200. As you know, the RGA uses a baud rate of 28,800, but EPICS does not seem to allow setting this baud rate. As a result, it reports the following error:  

drvAsynSerialPortConfigure ("RGA200", "/dev/ttyUSB0")
asynSetOption("RGA200", 0, "baud", "28800")
setOption failed Unsupported data rate (28800 baud)

How should this issue be resolved?

Feng  

— 

Eric Norum

eric at norum.ca