pcm.ac97 {                                                                                                    
    type hw                                                                                                   
    card 0                                                                                                    
    device 0                                                                                                  
}                                                                                                             
                                                                                                              
pcm_slave.sl2 {                                                                                               
    pcm ac97                                                                                                  
    rate 16000                                                                                                
}                                                                                                             
                                                                                                              
pcm.rc {                                                                                                      
    type rate                                                                                                 
    slave sl2                                                                                                 
}