CRESTRON CNTBLOCK Network Terminal Block
REMOTE CONTROL SYSTEMS
2DOC. 8055A
Specifications subject to change without notice.
INDICATORS:
NOTE Indicators are provided to denote an error with the net cable supplying network
power to the CNTBLOCK. The LEDs do not signify wiring problems that exist on the
network runs from the CNTBLOCK to other net devices.
Thereare three LED indicators located on the CNTBLOCKtop panel, refer to figure 1. The combinationof
two LEDs, NORM ON (Y) and NORM OFF (Z), and their three states of illumination, bright, dim, and off,
indicate whether wiring through the CNTBLOCK is correct. Refer to table 2 for LED illumination
combinationsand the associated wiring conditions.
Table 2. Wiring Conditions Per CNTBLOCK LED Illumination
CNTBLOCK LED ILLUMINATION
POSSIBLE WIRING CONDITIONS NORM ON (Y) NORM OFF (Z)
Correct Bright Dim
Bothnetwires disconnected Off Bright
Data Y net wire correct only Bright Bright
Data Z net wire correct only Off Dim
Datanet wires swapped Dim Bright
POWER
The green LED illuminates when 24 volts is supplied to the CNTBLOCK over the network. If the +24V
lineisimproperly connected, the POWER LED does not illuminate.
NORM ON (Y)
Thered LED brightly illuminates in combinationwith an illuminated POWER LED anda dimly illuminated
NORM OFF (Z) LED during normal operating conditions. Refer to table 2 for other states of illumination.
NORM OFF (Z)
The red LED illuminates dimly in combination with a brightly illuminated POWER and NORM ON (Y) LED
duringnormal operating conditions. Refer to table2 for other states of illumination.
INSTALLATION/SETUP:
Power Isolation
If additional power supplies are needed for a CRESNET II system, care must be taken to isolate
them from one another. The CNTBLOCK offers a convenient method for isolating network devices
which should be powered by separate power supplies. Removing the jumper from the circuit
board isolates the 24 V lines from one side of the CNTBLOCK to the other. The jumper is clearly
marked (JUMPER) on the circuit board.
