Changes

===Analog Radio Interface===

===Analog Radio Interface===

[[File:AnalogRadioInterface.jpg|left|Rev. C. Analog Radio Interface Board]]

[[File:AnalogRadioInterface.jpg|left|thumb|Rev. C. Analog Radio Interface Board]]

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<p>This interface <i>did</i> work well to allow me to do the initial development of the software, and first half a dozen deployments, since most of us that had it first already had Asterisk phone switches already in opertion, with spare ports on our channel banks.</p>

<p>This interface <i>did</i> work well to allow me to do the initial development of the software, and first half a dozen deployments, since most of us that had it first already had Asterisk phone switches already in opertion, with spare ports on our channel banks.</p>

===PCI Radio Card===

===PCI Radio Card===

[[File:PCIradiocard.jpg|left|Quad PCI Radio Card]]

[[File:PCIradiocard.jpg|left|thumb|Quad PCI Radio Card]]

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<p>After a few months of the system running stably (despite new additions all the time), we decided that better system integration was appropriate, so we (along with help from David Kramer) designed and produced the Quad PCI Radio Interface card. This allows interface between the PC and 4 separate radio systems simultaneously, via 8 pin modular connectors.</p>

<p>After a few months of the system running stably (despite new additions all the time), we decided that better system integration was appropriate, so we (along with help from David Kramer) designed and produced the Quad PCI Radio Interface card. This allows interface between the PC and 4 separate radio systems simultaneously, via 8 pin modular connectors.</p>

<p>For the next 2 years, we kept adding features, and refining the ones we had, and discovering that even though MANY people were QUITE interested in the technology, the price for entry was a bit high (for those who had no experience and wanted to just evaluate it). It became painfully obvious that something had to be done, somehow, to allow the hardware interface price to be lowered considerably without sacrifice in the quality of the technology.</p>

<p>For the next 2 years, we kept adding features, and refining the ones we had, and discovering that even though MANY people were QUITE interested in the technology, the price for entry was a bit high (for those who had no experience and wanted to just evaluate it). It became painfully obvious that something had to be done, somehow, to allow the hardware interface price to be lowered considerably without sacrifice in the quality of the technology.</p>

<p>After looking at many possibilities, including usage of a PC's internal audio subsystem (yuch! yuch! yuch!), it sure seemed that the only realistic chance we had was to get something reliably working with a USB interface.</p>

<p>After looking at many possibilities, including usage of a PC's internal audio subsystem (yuch! yuch! yuch!), it sure seemed that the only realistic chance we had was to get something reliably working with a USB interface.</p>

<p>Experiments with USB several years previously show it to be utterly flaky and useless on Linux, and not much better even on Windows. But, since that's about all that's available any more (other then maybe Firewire, which is more or less the same thing) I figured we should re-visit the possibility of stable USB, and did so and found success. Its good that things change.</p>

<p>Experiments with USB several years previously show it to be utterly flaky and useless on Linux, and not much better even on Windows. But, since that's about all that's available any more (other then maybe Firewire, which is more or less the same thing) I figured we should re-visit the possibility of stable USB, and did so and found success. Its good that things change.</p>

<p>After some looking around, I found the <a href="http://www.cmedia.com.tw/?q=en/USB/CM108"> C-Media CM-108</a> USB Sound IC. It is VERY simple, VERY high quality, VERY reliable and VERY inexpensive. Even already make USB sound cards (well, sound devices, they're awfully small to call a card) that could easily be modified for development and testing purposes.</p>

<p>After some looking around, I found the [http://www.cmedia.com.tw/?q=en/USB/CM108 C-Media CM-108] USB Sound IC. It is VERY simple, VERY high quality, VERY reliable and VERY inexpensive. Even already make USB sound cards (well, sound devices, they're awfully small to call a card) that could easily be modified for development and testing purposes.</p>

 

<p>So after some testing and verification of the USB hardware, I went to my friend Steve Henke, W9SH (who had already done some major work on the IAXRPT project for us), and asked him to use his amazing DSP skills to write code to do two-way audio processing right in the PC (going along with the Zapata Telephony motto of <i>"We don't need no stinkin' DSP!"</i>), which, happily he did.</p>

<p>So after some testing and verification of the USB hardware, I went to my friend Steve Henke, W9SH (who had already done some major work on the IAXRPT project for us), and asked him to use his amazing DSP skills to write code to do two-way audio processing right in the PC (going along with the Zapata Telephony motto of <i>"We don't need no stinkin' DSP!"</i>), which, happily he did.</p>

<p>We now have functional DSP code and channel interface code to allow USB devices to interface with <a href="http://app-rpt-svn.ohnosec.org/viewvc/projects/allstar/?root=svn">App_Rpt</a> and <a href="http://www.asterisk.org">Asterisk</a>, allowing high-quality, yet inexpensive interconnection with radio devices.</p>

 

<p>We now have functional DSP code and channel interface code to allow USB devices to interface with App_Rpt and Asterisk, allowing high-quality, yet inexpensive interconnection with radio devices.</p>