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.