The unpacked data format for the svx-driven front ends is as follows:

class UnpDataChunk:
 
    sysid : 
        FT_L1


    class Channel:

        class MCHID:

            sysid : 
                FT_L1

            modid : ( Header VRB = 15 )
                bits 0-3  = slot # = VRB = seq# = 12  (CFT)
					       = ....
                bits 4-10 = crate # = 80 (CFT)
				    = ......

            chanid : for VRB 
                = -1	     for header
                = 0          for track counts
		= Track ID

        version : VRB and VRBC
            version = 1
    
        data : Header
	    data [0] = bit  0-15  => Rotation No.  = 0 in MC (?)
	    	     = bit 16-23  => Bunch number  = 0 in MC (?)
	    data [1] = bit 0-7   => Algorithm Major Version  = 1 ( useless for us )
		     = bit 8-15  => Algorithm Minor Version  = 1
	    data [2] = bit 0-7   => Processing ID ( a kind of version no. ) = 1 ( now )
	    data [3] = bit 0-7  => Global Error = 0000 0001  ( check Manuel's Web page 
                 	            \\d0server1\users\manuel\presents\E_Review_99.pdf   p.14


        data : track counts :
            data [0] = no. of track in the 1st pt bin
            data [1] = no. of track in the 2nd pt bin
            data [2] = no. of track in the 3rd pt bin
            data [3] = no. of track in the 4th pt bin

	data : tracks
	    data [0] = signed pt
	    data [1] = 16 bits for a track 
	    data [2] = bit 0-7  FE address ( which sector )
                       bit 8-15 phi address

//            At the end, there should be a longitudinal parity.