Notices

I am wondering if anyone has done any work on getting soundmodem running on the N800:
http://www.baycom.org/~tom/ham/soundmodem/

I have been messing around a bit trying to get it working by building it from the Debian sources, and it builds OK, but when I run it I get

sm[2607]: Unable to set period time 15000 for capture: Invalid argument

I'll have to start delving into the ALSA API, I expect, based on this error. If anyone has any experience with soundmodem on the N800 (or N810), it would be great to hear from you. I'm trying to build a portable packet system out of the N800 and a Yaesu VX-7R.

73,
Frank Smith
VE1FIS
ve1fis@gmail.com

Just found this thread. Any updates?

> sm[2607]: Unable to set period time 15000 for capture: Invalid argument

I have no idea really but hazard a guess that sampling can only be done at 8KHz.

I've never tried doing anything with soundmodem on the NITs, but I have in the past built a kernel with AX.25 support, and built debs for libax25, etc.

Nothing new on using the built-in audio.

I have a USB sound dongle, though, that I thought I'd try to get working with the N800 at some point. If I have any luck I'll post my results.

Any thoughts about the 8KHz sampling limit suggestion above?

Would it happen to be one of of these USB sound cards?



Sound modem + Maemo Mapper which now has APRS support would be a great tool !

No, the original error I had was using the built-in audio.

Yesterday I built a USB cable so that I could plug in a dongle like the one you pointed out. I had purchased three from dealextreme.com, and one of them I was able to get working well with my Yaesu VX-7R and Ubuntu laptop running soundmodem and Xastir.

I plugged it into the N800, and it looked like the kernel recognized it... it created /dev/dsp1 for instance. I configured soundmodem to use soundcard mode on /dev/dsp1, and ran soundmodem with no errors. I hooked it up to the HT where there were APRS packets flying around, but no joy yet.

I figure the next thing to do will be to figure out how to set the audio levels. I have built alsamixer, but have not been able to use it to configure the USB audio yet. The alsa.conf on the N800 looks quite stripped down. I think I might need to figure out how to get it to support the typical hw:1,0, plughw:1,0 device names.

I will post updates as I make progress. If anyone has any suggestions please jump in at any time.

I'll write more later, but I see my prior post was not clear, I was talking about the 8KHz sampling limit with the built in 'sound card'.


I've noticed those USB dongles to be very load sensitive, in fact when the output had a ~100 ohm load on it, it substantially muted the input. If I remember right, a ~1K resistor in series with the headphone audio line fixed this problem. Search this forum for those USB sound card dongles and as well as alsa, there are a few posts about it here.

After re-reading, I see that your post was clear.

To go into more detail, I purchased the following dongles from dealextreme.com:

1. http://www.dealextreme.com/details.dx/sku.22475
2. http://www.dealextreme.com/details.dx/sku.624
3. http://www.dealextreme.com/details.dx/sku.5831

It was (3) that I had success with. The total for all 3, including shipping, was about $12 Canadian, so 1/3 wasn't bad. I also have this one on its way:

4. http://www.dealextreme.com/details.dx/sku.8978

Dongles (1) and (2) gave me these errors on x86 ubuntu, and I have not tried them on the N800:

pulseaudio[3294]: alsa-util.c: Device hw:1 doesn't support 44100 Hz, changed to 24000 Hz.
pulseaudio[3442]: module-alsa-sink.c: Your kernel driver is broken: it reports a volume range from 0.00 dB to 0.00 dB which makes no sense.

Yes, "#3" is what I use as well. I'm more of a hardware guy than a software guy.

There is some good info in this thread: http://talk.maemo.org/showthread.php?t=16952