Known issue with Comcast service (blinking ONLINE light)

Attention Comcast customers:

This issue affects a small percentage of Comcast customers installing a Zoom Model 5352 for the first time. Please follow the Quick Start instructions that came with your Model 5352 cable modem. After the modem is connected to the cable and powered up, the modem’s lights will blink. The POWER, DS and US lights should become solidly on.

If the modem’s ONLINE light continues to blink for over 45 minutes after the POWER, DS, and US lights are solidly on, this indicates that there is no Internet connection. In that case, you will need to contact Technical Support by submitting an inquiry. Please provide the following information:

• CM MAC address from the Zoom device - located on the bottom label
• Serial Number (S/N) from the Zoom device - located on the bottom label
• The name registered to your Comcast account
• The phone number registered to your Comcast account
• Your e-mail address

We will forward the above information to an upper level Comcast technician, who will modify a network setting that will allow your cable modem to come online. The connectivity issue is related to IPv6 deployment in some Comcast service areas and only affects one Zoom model, Model 5352, and some modem/routers of other brands supporting IPv6. We believe that Comcast will resolve this issue soon.