Using the power of Prima Logic Language, you can program any CDQPrima model to automatically fall back to a single ISDN 'B' channel and a lower bit rate should a line fail when using Layer 3. In addition, this function is automatic, requiring no intervention once programmed. The example shown here illustrates just how easy it is.

Here's how to do it:

• Create three Quick Configurations for the algorithm setups — 2-line, line 1 only and line 2 only.
  
• Define virtual actions to load the selected configurations.
  
• Define event-to-action statements to determine the number of connected lines and execute the appropriate Quick Configuration.

1. Create three Quick Configurations as follows:
   
   

   Encoder/decoder algorithm:	MPEGL3
   Encoder/decoder bit rate:	112 or 128 kb/s (use the highest available for your connection)
   Encoder Sample rate:	32 or 48 kHz
   Encoder algorithm mode:	Joint stereo
   Encoder/decoder line format:	CCSL12
   Decoder independent:	YES

        
   The CDQPrima returns ID number xx when this configuration is entered
   
   

   Encoder/decoder algorithm:	MPEGL3
   Encoder/decoder bit rate:	56 or 64 kb/s (use the highest available for your connection)
   Encoder Sample rate:	32 or 48 kHz
   Encoder algorithm mode:	Mono
   Encoder/decoder line format:	1 line, line 1
   Decoder independent:	YES

   
   The CDQPrima returns ID number xx when this configuration is entered
   
   

   Encoder/decoder algorithm:	MPEGL3
   Encoder/decoder bit rate:	56 or 64 kb/s (use the highest available for your connection)
   Encoder Sample rate:	32 or 48 kHz
   Encoder algorithm mode:	Mono
   Encoder/decoder line format:	1 line, line 2
   Decoder independent:	YES

   
   The CDQPrima returns ID number xx when this configuration is entered
   
   
2. Set up 4 Virtual Actions as follows:
   
   
   

   CVA 0 CSD xx	Load Quick Configuration xx, 2-line, lines 1 & 2.
   CVA 1 CSD yy; DAL MPEGL3	Load Quick Configuration yy, 1 line, line 1. Set decoder algorithm to Layer 3.
   CVA 2 CSD zz; DAL MPEGL3	Load Quick Configuration zz, 1 line, line 2. Set decoder algorithm to Layer 3.
   CVA 3 CTM 0 3	Start a 3-second timer for delayed start.

   
   
3. Set the following Event-to-Action Logic to determine which Virtual Action to execute:
   
   
   

   CEA VA0 +(CD1 & CD2)	Execute VA0 when connected on 2 lines.
   CEA VA1 +(CD1 & !CD2 & !TI0)	Execute VA1 when only line 2 is connected and the timer is not running.
   CEA VA2 +(!CD1 & CD2 & !TI0)	Execute VA2 when only line 1 is connected and the timer is not running.
   CEA VA3 +(CD1 & CD2 & FRAMED)	Execute VA3 when both lines connect and framed.

Here's how these 8 lines work:

• If 2 lines are connected, load the 2-line configuration.
  
• If only one line connects, or if any line drops, load the appropriate single line configuration.. 
  
• A timer is used to delay the start of the routine until the CDQPrima is framed.