That's what Charter asked me to do. Until last week, I didn't have any problem with my Zoom cable modem. But last week, my 20Mbps cable modem was checked to 1Mbps according speedtest.net. So I contacted Charter Comm. and at the time, they said to me that they are fixing something. But after a week, it's still 3Mbps so I contacted their CS again.

Long story short, this time the agent said I need to buy a new modem complying DOCSIS 3.0. Because of the provision they added, he said, I am having 3Mbps now. According to the agent, provisioned speed is conflicted with my modem under 12Mbps, and becomes dominant over actual speed. Suppressing all the emotions going through my head, does that advice make any sense? Why would a modem, working fine before, become so slow with provision change?

Buying a new modem does not really matter but I am afraid that it may not fix the suddenly slow internet speed. Any advice would be appreciated.

UPDATE: I bought Motorola SB6120 SURFboard today and wasted a couple of hours to adjust my router, which is totally my fault as this is my first time to do that. But Charter's agent was right as my internet speed is 20Mbps right now. I am all happy now. Thanks for your responses, guys.

  • Which Zoom cable modem? Aug 1, 2011 at 19:38
  • Look in to if your modem provides a management interface. Most modems have an internal webserver that will provide you a few connection quality metrics and give you a first idea if your connection might be the trouble. Aug 2, 2011 at 0:38

2 Answers 2


Purchase a DOCSIS3.0 modem. When it gives the same results. Have them come out and fix the interference/signal issues that you're most likely having. The DOCSIS2.0 modem you have should safely support 20mbps and even up to 30mbps. Anything beyond this, you would definitely need a DOCSIS3.0 modem. The guy at Charter most likely didn't know the answers to your question and they don't make money sending people out to fix their own issues. Without some sort of proof, they won't believe that you tried a new modem. Also, if I were you, I would tell them that it was their upgrades that they performed which caused your modem to be fried. I would demand a new one on their dime. Flip it back onto them!


Those modems fail frequently, so yes, it is standard for support to suggest that you replace your modem if they don't see any other problems on the connection. (The modems are inexpensive and mass-produced; and although I can't tell you how they fail, I know that replacing them solves connectivity issues so often that I know that they do.)

If replacing the modem does not solve the issue, however, you can request a truck roll to check the actual physical connection.

  • I would suggest replacing the modem, then. If it doesn't help you can probably auction the new one on eBay without losing too much money.
    – goblinbox
    Aug 1, 2011 at 20:57
  • It's not so much that the ISP made this situation as that the hardware is very cheap and fails often.
    – goblinbox
    Aug 25, 2011 at 4:56

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