Circuit state indicator (national use)


           8  7  6  5  4  3  2  1
        1  H  G  F  E  D  C  B  A
        :
        :
        n  H  G  F  E  D  C  B  A

The number of octets in the circuit state indicator parameter field is equal to the specified range + 1. Each circuit state indicator octet is associated with a circuit identification code such that octet n is associated with circuit identification code m + n ( 1, where m is the circuit identification code contained in the message. The following codes are used in each circuit state indicator octet:
a)      for bits D C = 00
        bits
B A     Maintenance blocking state
0 0             transient
0 1             spare
1 0             spare
1 1             unequipped
        bits H-E        Spare

b)      for bits D C not equal to 00
        bits
B A             Maintenance blocking state
0 0             no blocking (active)
0 1             locally blocked
1 0             remotely blocked
1 1             locally and remotely blocked
        bits
D C             Call processing state
0 1             circuit incoming busy
1 0             circuit outgoing busy
1 1             idle
bits
F E             Hardware blocking state (Note)
0 0             no blocking (active)
0 1             locally blocked
1 0             remotely blocked
1 1             locally and remotely blocked
        bits H-G        Spare
        NOTE - If bits F E are not coded 0 0, bits D C must be coded 1 1.