[App_rpt-users] USB fob choppy/stuttering audio

[Eric Fort]

Rob,

It was not my intent to “dump on” you for what does indeed seem to be a well known but poorly documented problem. I simply was posing a question as to why so many have chosen the path of usb when stable and well engineered solutions that have not these problems came before and worked so well. It was not meant or intended to be directed at you specifically and if it seemed that way I apologize.  I realize that the Raspberry pi only leaves us with using usb as an option.  I personally look at that and would say that then maybe the Raspberry pi isn’t the best platform to be using and maybe we ought look at better and more robust hardware options such as the single board computers that have multi channel tdm based sound busses and dual programmable real-time subsystem processors where hardware can be built and interfaced based on proven tdm bus concepts. Again this is not a reflection on you, it’s intended as a general query as to why things are as they are. Marshal gave a good reply to that and it seems to be an issue of cost. It also seems to be one gets what they are willing to pay for.   Maybe we could document this better, maybe we could work on updating some hardware designs so we have a viable alternative to usb. Theese seem like areas worth looking at. As for your current issue with usb. Again this query is not pointed at you, but more generally why things are as they are, and what may be done about it. 

Eric
Af6ep

Sent using SMTP.

> On Mar 31, 2019, at 10:01 AM, Rob Noll <rob at nollmail.com> wrote:
> 
> I’m looking for assistance solving this issue, and particularly how to check the device string in the configuration file, and/or how to change the sample rate of the audio stream sent to USB.
>  
> I’m not sure why you chose to unload on me for what you seem to be claiming is a well known issue, but from my searching does not appear to be well publicized.  Nor am I sure what I may have said that would cause antagonization.  I was merely looking for some assistance with an issue that I hoped maybe others had encountered and knew of a cause or solution.
>  
> That said, here are some answers to your questions:
> >>> why does it seem that most everyone has gone this route against the above sage wisdom
> Where is this sage wisdom?  I’m new to ASL.  I read the wiki page.  I saw no warnings against USB, in fact, I there were links to USB devices.
>  
> >>> rather than using something more akin an e&m interface like the pci radio cards Jim designed
> I don’t know Jim, don’t know where to buy his products, and there are no PCI interfaces on a Raspberry Pi.
>  
> >>> the interface boards that plugged into an fxs? Port and broke out e&m, providing keying by polarity reversal of the battery voltage
> An fxs port is an analog telephone port, isn’t it?  Again, not available on a Raspberry Pi, and although I’m sure I could come up with a way to key the transmitter in question based on a reverse polarity battery signal, that does not seem like a very straightforward undertaking.
>  
> >>> Apparently usb not so much and apparently this is a long standing problem with usb
> I disagree.  I’ve used plenty of USB audio devices in the past with no problems whatsoever.  In fact, this very device works fine when used as a sound card on a PC.  So if there are any longstanding issues, it would appear from a cursory glance to be with asterisk’s passing of the audio.
>  
>  
> From: App_rpt-users <app_rpt-users-bounces at lists.allstarlink.org> On Behalf Of Eric Fort
> Sent: Sunday, March 31, 2019 12:49
> To: Users of Asterisk app_rpt <app_rpt-users at lists.allstarlink.org>
> Subject: Re: [App_rpt-users] USB fob choppy/stuttering audio
>  
>  
> On Mar 31, 2019, at 9:08 AM, Bob Pyke <k6ecm1 at gmail.com> wrote:
> 
> Sorry, not with ASL. I found it best to let it set it, but I check to make sure. ASL is much better than the original based on CentOS. I’ve had the Linux mix it up, but not had that issue since DIAL and ASL.
>  
> As Jim has said many times, “friends don’t let friends do USB” :-)
> 
> Thanks,
> Bob
> K6ECM
> 73
>  
>  
> I have heard many times of the problems using usb with asterisk and app_rpt. So why does it seem that most everyone has gone this route against the above sage wisdom rather than using something more akin an e&m interface like the pci radio cards Jim designed and built or the interface boards that plugged into an fxs? Port and broke out e&m, providing keying by polarity reversal of the battery voltage. Both solutions work rock solid with no issues. Apparently usb not so much and apparently this is a long standing problem with usb. In thinking about this I’m also curious if the design files for the pci radio interface boards may be available as they’d likely be a good start for an update to a more current interface standard. 
>  
> Eric 
> Af6ep 
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