Read Me: Troubleshooting Highspeed Cable broadband

Vodafone Ninja
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Registered: ‎02-11-2014

Read Me: Troubleshooting Highspeed Cable broadband

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by Vodafone Ninja Vodafone Ninja Vodafone Ninja
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Hi all,


After helping out a few customers with cable modem issues lately I thought I’d put together a few tips and tricks that might help you if you’re having issues getting a connection.


The following steps are to help you figure out if your cable broadband connection is working or not. Many people will call in to report that their Internet isn’t working at all. Now, the good news with a Cable connection is that there are some straightforward ways to figure out what’s causing your particular issue. The first is you’ll need to identify what type of modem you have installed. With cable connections there are two different types of modems that our customers have installed.


The first type is a Motorola S85101 modem that looks like this:



This modem is easy to read because it needs to have 4 SOLID green lights and 1 flashing green light. The 4 solid green lights can indicate Sync

-If any of these lights are flashing, there could be something going on. Best things to check are the cable that connects at the “Coax” port on the back of the modem or at the point where it connects to the splitter (this can either be in the floor or the wall) but you should never unscrew these connection points. Just ensure they’re still plugged in and aren’t damaged.

  • The flashing PC Activity light indicates data transfer
    -If this isn’t flashing, the most likely cause is either the Ethernet cable that goes from the modem to the computer/router is not connected/turned on.
  • The bottom light is the standby light (which will never show as the standby button was disabled due to modems being accidentally turned off and people calling in about it reporting it as a fault)


The second type is a Cisco DPC3008 modem like this:


This modem is easy to read because it needs to have Power, Solid DS and US and a Link light

  • Solid DS and US indicates Sync
  • Link light being solid indicates the cable is connected and the Link light flashing indicates data transfer.
    -If this is not on at all, check to ensure the Ethernet cable is connected at the back of the modem and at the router/computer


If you have all of the correct lights but no Internet connection still, it could indicate that the device/s you have connected to the modem aren’t configured to connect to the modem or you have no data transfer (more on this later) In the former instance, you will either have a cable wireless router connected or a computer hard wired to the modem. The trick with this is that for a device to “talk” to the cable modem, they’ll need to be manually configured with the correct settings to do so. If they don’t have the correct settings, they won’t be able to communicate and none of your services will work.

***EDIT - Sorry for this, it's very late BUT Cable connections now being assigned Dynamic IP addresses means that routers and devices themselves no longer need manual config - Yay!***


To configure a device to talk to either cable modem you’ll need to know:

  • Your assigned Static IP address
  • The Subnet Mask which is “”,
  • The default gateway which is the same as your IP address but the last digit is always”.1” (eg: “XXX.XXX.XXX.1”)
  • And also the Primary and Secondary DNS servers which are “” and “”


To manually configure a computer to communicate with the Cable modem you can follow these instructions here:


So, that's pretty much all you'll need to know about our cable modems! Some people will have the modem plugged into just one computer like described above, but most people now have the modem plugged into a "wireless router" so you can share the Internet connection with multiple computers, and the wireless router makes a wifi network at home for devices like laptops, iPads and phones. If that's what you're setting up start off by looking through the info that comes with your wireless router and enter the same settings mentioned above. The wireless router connects directly to the modem instead of the single computer described above.

Let us know if you have questions about cable modems or wireless routers. Some wireless routers can be a bit complicated so you might need to contact the manufacturer directly, but please post a topic in the Modems & home Wi-Fi section and another member of Vodafone Community might be able to help out.

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