28 4028103 Rev A
Front Panel LED Status Indicator Functions
Initial Power Up, Calibration, and Registration (AC Power applied)
The following chart illustrates the sequence of steps and the corresponding
appearance of the cable modem front panel LED status indicators during power up,
calibration, and registration on the network when AC power is applied to the cable
modem. Use this chart to troubleshoot the power up, calibration, and registration
process of your cable modem.
Note: After the cable modem completes step 8 (Registering with Call Agent), the
modem proceeds immediately to Normal Operations (AC Power applied).
Front Panel LED Status Indicators During Initial Power Up, Calibration, and Registration
STEP → 1 2 3 4 5 6 7 8
Front Panel
LED Power
Up Self
Test Downstream
Scan Downstream
Signal Lock Ranging Request
IP
Address
Registering Register
with Call
Agent
1 POWER On On On On On On On On
2 DS Blink On for 1
second Blink On On On On On
3 US Blink On for 1
second Off Off Blink On On On
4 ONLINE Blink On for 1
second
Off Off Off Off Blinking On
5 LINK1 Off On for 1
second
On or Blink On or Blink On or
Blink
On or
Blink
On or Blink On
1 The LINK LED is on whenever a PC is connected to the modem, and it blinks to indicate that data is being transferred. If the
modem provides telephone service only and is not connected to a PC, the LINK LED is OFF.