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johnny213's avatar
johnny213
New Contributor II
3 years ago

Cable modem dropping connection 1 - 2 times a day

Cable modem (newish tp-link) loses connection 1 to 2 times a day. A reset fixes it, but it really eats into my daily routine to have to take care of this, and it has dropped during important Zoom calls and other work meetings over the past year. I'm pretty sure this is on Cox's end, since this same cable modem worked perfectly with no issues at my last address (also Cox).

I checked the system logs, and found multiple iterations of the following when the connection dropped this morning (MAC addresses deleted):

Tue Mar 22 06:47:43 2022 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=
Tue Mar 22 06:47:39 2022 Critical (3) REG RSP not received;CM-MAC=
Tue Mar 22 06:47:08 2022 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=
Tue Mar 22 06:47:06 2022 Critical (3) No UCDs Received - Timeout;;CM-MAC=
Tue Mar 22 06:46:49 2022 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=
Tue Mar 22 06:46:45 2022 Critical (3) Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=

Post-reset, everything's good. Current power levels range from downstream -18.5 dBmV to -17.8 dBmV with SNR 30.7 dB to 31.6 dB, and upstream 57.0 dBmV.

I've tried calling tech support in the past, but the advice has usually defaulted to "reset your modem"...which isn't sustainable for me anymore at this rate.

Any advice would be appreciated. Should I record power levels when the connection drops again and post here?

11 Replies

  • Bruce's avatar
    Bruce
    Honored Contributor III

    What's the make and model of your TP-Link?

    I agree your power looks out-of-spec, your peak SNR looks low and if Up is 57 dBmV, it's at the brink of no connectivity.

    • johnny213's avatar
      johnny213
      New Contributor II

      Yup; I checked the approved list a few years ago. I have a 7610, and it looks like it's still approved.

      • Bruce's avatar
        Bruce
        Honored Contributor III

        Yes, it'll still work but I tripped on "newish."

        As Mouth suggested, snoop along your coaxial cable for a splitter.  A splitter is just a connection device, piece of hardware.  Also check behind your wall plate for splitters.  You may just have to replace it.  Cheaper than a tech if it fixes.

  • Bruce's avatar
    Bruce
    Honored Contributor III

    Just a long shot, you may try factory-resetting the modem.  There is a difference between your "reset" in your post and a reboot.  You can also reset via your Cox account.  A reboot just reboots the modem as is, but an online reset does other stuff.

    So...there are 3 types: a reboot, an online reset & a factory reset.

    Search T4:

    www.cox.com/.../TP-LINKTC7610_UserGuide.pdf