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Troubles's avatar
New Contributor
3 years ago

Arries tm3402

I noticed the forum has been locked on the problem with this modem. We got this modem two and a half months ago. The internet went out before on it, but now it is going out over and over again in a day. The previous post was from TWO YEARS AGO about the issues with this modem!  I can’t believe Cox is still giving out a modem that has known problems. We too, like the person from two years ago, have our own new netgear nighthawk router, so we didn’t need the panoramic. They told us we had to go to this modem if we had our own router when we went to the Gigablast internet package KNOWING the thing doesn’t work. The last rep we spoke to tonight claimed they had been recalled (not sure if that’s accurate), and told us they have the new ones and said the problem was very NEW. Well, it looks like the truth is that the problem is at LEAST TWO YEARS OLD. When you rely on the internet for your job, this is very problematic. It really irks me that they continue to do this putting jobs at risk with all the people who went home to work over the past year. I think I will check with the BBB about this. This is so wrong on so many levels, and the guy in the post two years ago said he got three boxes issued to him by Cox and a tech out, and the problem persists. The rep set me up to pick up a new modem claiming the issue was new and they had a recall and they just updated the model. Plus a truck roll is set for Friday.

Is there another option? Maybe we should go back to the lower speed and get the older box back.

5 Replies

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  • bryaninphx's avatar
    Valued Contributor

    There is a known, random, issue with this eMTA (ARRIS TM3402A) it's a Voltage Bug in the Intel chipset. Just swap it out at the Cox store for another one, just make sure its brand new and not a refurbished one.. Luckily, I have only had to replace mine once in the last few years. Constant DHCP issues obtaining an IP Address from the CMTS, once the issues arise.
    On the customer side it appears as a dead WAN Port or a bad router, Rebooting the modem often does not help. You can often re-acquire an IP Address by connecting the modem to a different MAC Address, either a different router or the PC directly, and then move it  back to the original router, but that solution is very temporary.

    I don't know if the latest Firmware Update includes a fix or not. Mine is as follows:
    Firmware Name:    TS11.02.095_030921_711.PC20.03.X1
    Firmware Build Time:    Tue Mar 9 18:50:24 EST 2021

  • Bruce's avatar
    Honored Contributor III

    If you subscribe to Cox Voice (landline), you need the TM3402 because it's also a telephone modem.

    Internet going out could be anything.  Why do you suspect the modem?

  • Bruce's avatar
    Honored Contributor III

    As far as another option, you can buy your own modem and install it with the TM3402.  You'll just have to call Cox to activate your new Internet modem..

    I had the TM3402 as an all-in-one device for my services but it started fumbling with connectivity.  I still had my previous DOCSIS 3.0 so as an interim solution, I installed it alongside the TM3402.  TM3402 was for telephone; D3.0 was for Internet.  It worked.  Internet service was great so I prolonged replacing the TM3402 for another all-in-one device.

    Two years later, Internet service has still been great and I haven't had any issue with it.  I only have the 150 Mbps plan so the D3.0 is good enough.

    As long as your potential Internet modem is on the Cox Approved List, you should be good-to-go.

  • JonathanJ's avatar
    Former Moderator


    bryaninphx is correct there is a known Intermittent connectivity issue with the Arries TM3402. We suggest swapping it out. You can swap it out at a solution store near you. We can also drop-ship one, simply email your full name and address to

    Jonathan J
    Cox Moderator

  • bryaninphx's avatar
    Valued Contributor

    I just noticed my old ARRIS TM3402A that had the bug was Hardware Revision 7 (HW_REV: 7)

    The replacement is a Hardware Revision 8 (HW_REV: 8)