One of it's downfalls if the lack of an on-board input. But once you add a USB sound fob, Echolink, remote rig applications, IRLP, and decoding various digital modes like PSK, and so on, are all a reality.
Finding a USB sound device and setting it up can be aggravating.
I recommend the SYBA SD-CM-UAUD USB CM119 audio adapter.
If lsusb doesn't report it as below, you have the wrong one:
root@pi:~# lsusb
Bus 001 Device 005: ID 0d8c:000e C-Media Electronics, Inc. Audio Adapter (Planet UP-100, Genius G-Talk)
Next you need to make the usb sound card (0) the default audio device
Check yours like so: cat /proc/asound/modules
0 snd_bcm2835
1 snd_usb_audio
Edit /etc/modprobe.d/alsa-base.conf comment out "options snd-usb-audio index=-2"
You want ""options snd-usb-audio index=0"
After a reboot it should always appear in this order:
0 snd_usb_audio
1 snd_bcm2835
Take this one step further and comment out the kernel module for the onboard sound and add the usb
cat /etc/modules should look like:
#snd-bcm2835
snd-usb-audio
While, I did not find the following necessary in my case, I have read to get better latencies out of USB audio devices, it is suggested to also add:
options snd-usb-audio nrpacks=1
pcm.dmixer {
type dmix
ipc_key 1024
slave {
pcm "hw:0,0"
period_time 0
period_size 1024
buffer_size 8192
rate 48000
}
bindings {
0 0
1 1
}
}
pcm.asymed {
type asym
playback.pcm "dmixer"
capture.pcm "hw:0,0"
}
pcm.dsp0 {
type plug
slave.pcm "asymed"
}
pcm.!default {
type plug
slave.pcm "asymed"
}
pcm.default {
type plug
slave.pcm "asymed"
}
ctl.mixer0 {
type hw
card 0
} Since there are some USB issues, I suggest setting the device to boot the USB hub in USB 1.0 mode, this should fix choppy audio. (I did not find this necessary in my case, but it's not a bad idea)
Add "dwc_otg.speed=1" to /boot/cmdline.txt.
Pulseaudio might be part of your raspberry wheezy default image. Personally I am not a fan of it, and have read it wasn't working well on the Pi. I am not sure if that still holds true. I just removed it:
apt-get purge pulseaudio
I recommend replacing it with Alsa. It has been around a bit longer:
apt-get install sox alsa-oss alsa-utils alsa-tools
Also, I suggest updating the firmware on your Pi.
https://github.com/Hexxeh/rpi-update/
This should be a good starting point for most. Hopefully in the future, newer Raspberry wheezy images can make this a bit easier, and more kernel support for other USB sound FOBs.
For my fellow hams you may want to check out these places to congregate:
https://groups.io/g/RaspberryPi-4-HamRadio/
http://amateurradiopi.com/forum/
And for those of you still interested in D-Star:
http://groups.yahoo.com/group/RaspberryPi-DVAP/
I have been running my Pi using a 5 volt, 1 amp supply via the micro USB power port. I do not use a USB hub. My model B rev 2 has been running reliably for a few weeks now.
Just as a note. If you are making connections to the GPIO for keying a radio or whatever, check your local Radio Shack for "Schmartboard Jumpers ." These are a new thing they are carrying, and are handy.
