Ultra-High Speed Cable Modem
The Arris CM820A router has No WiFi, 1 N/A ETH-ports and 0 USB-ports.
It is also known as the Arris Ultra-High Speed Cable Modem.
CM820A router specifications (specs)
RAM: 128 MiB
Flash: 16 MiB
Custom firmwares: None
WiFi: No ()
WiFi bands: n/a
WiFi throughput: n/a
ETH: 1 x N/A port
Arris CM820 review (quick overview)
Here is the quick comparison of how the Arris CM820 compares to other routers on our site:
For a full list of routers and how they compare to the CM820A, check the Router Buying Guide which will help you buy the most price-competitive router.
Hard reset instructions for Arris CM820A
If your CM820A router is not working as it should, dropping connections or not
responsive, you should first do a reset of the router to see if the problems persist. Other
scenarios where you might want to reset your router is if you've forgotten the password or
misconfigured it and can't get access anymore.
Your can reset your Arris CM820A in the following way(s):
The 30-30-30 resetThere are no specific instructions for this model yet, but you can always do the 30-30-30 reset as follows:
- When router is powered on, press the reset button and hold for 30 seconds. (Use a paper clip or something sharp)
- While holding the reset button pressed, unplug the power of the router and hold the reset button for 30 seconds
- While still holding the reset button down, turn on the power to the unit again and hold for another 30 seconds.
This process usually works for resetting any router to it's factory setting.
If that doesn't work be sure to check out the
questions and answers
incase someone else has had similar problems resetting their router.
Note: It is worth reading more about how to reset routers with the 30 30 30 reset and what the risks and considerations are when resetting your router this way, instead of just rebooting it.
Default factory settings for Arris CM820A
If you have performed a reset of your CM820A device or not changed the defaults, you should be able to access it with the following settings:
Note: If you are using the default settings you should change them to increase security and prevent unathorized access to your network.
Staying up to date with the latest firmware is a good idea to keep your router even more
from various security flaws.
If you want to squeeze a little bit of extra functionality out of your router, consider flashing an open-source firmware like dd-wrt, openWRT or LEDE. Flashing a custom ROM can greatly increase the stability and functionality of your old router.
Following are the firmwares that we have identified existing for the Arris CM820A:
Arris stock firmware for the CM820A
Stock firmwares for the CM820A are available under the download section on the modem's support page. You can also refer to the router's manual for instructions on how to upgrade the firmware.
Report error on page
(If info is incorrect)