And the yellow alarm should be cleared on the Linux command line. Use dahdi_tool and dahdi_cfg -vv at the Linux command line to test that. PBX in a Flash. Dahdi_tool A nice tool to see what your boards are doing. DAHDI-linux documentation; DAHDI-tools documentation; Zaptel; Sample installation.
Description: I ran into a situation where I wanted to use one of the Digium transcoder cards installed in a machine to convert u-law to G.729A, without needing to install Asterisk. This command line utility grew out of that need. The original version of this code was a phase-locked implementation that used blocking FDs for the input, output, and transcoder interface, but I wanted to make it perform better and changed it to use multiplexed I/O. As this is the first time that I have really used select in something other than hobby code, that the implementation may need some work. That being said, it is functional and I am able to convert audio to and from G.729A.
Description: I ran into a situation where I wanted to use one of the Digium transcoder cards installed in a machine to convert u-law to G.729A, without needing to install Asterisk. This command line utility grew out of that need.
The examples in this document use a stacked solution; however, the same commands can be run on a standalone switch. The information in this document was created from the devices in a specific lab environment. Prerequisites Requirements Cisco recommends that you have knowledge of these topics: • TFTP • FTP Components Used The information in this document is based on the Cisco Catalyst 3850 Series Switch that runs Cisco IOS-XE Versions 03.03.00 and later. 
Dahdi Download
The original version of this code was a phase-locked implementation that used blocking FDs for the input, output, and transcoder interface, but I wanted to make it perform better and changed it to use multiplexed I/O. As this is the first time that I have really used select in something other than hobby code, that the implementation may need some work. That being said, it is functional and I am able to convert audio to and from G.729A.