Arris CM820A (Comcast Version) DOCSIS 3.0 Cable Modem [Bulk Packaing] Backwards compatible with DOCSIS 1.0, 1.1, and 2.0 . CM820A DOCSIS 3.0 compliant. Comcast Compatible! (and more!) 8x4 downstream/upstream channel-bonding with superior throughput. Note: please contact the ISP to check the compatibility. Note: please contact the ISP to check the compatibility. 10/100/1000 Base-T Ethernet interface Best troubleshooting advice for this item: 1) Always verify if your cable company will allow you to use or own this item 2) Always do the online setup first, most of the time the firmware update will be automatic this way if it is needed. 3) Demand a supervisor if a CSR (customer service rep) will not assist in the setup 4) Customers can always contact us through messaging for assistance we respond to all messages with 24 hours 365 days a year. NOTE: Customer's must verify if their cable company will allow them to use this prior to purchasing even if they have the exact same model some of these modems are pre-programmed from their cable company so their cable company must update the firmware in order for it to work in some cases. Verify compatibility prior to purchasing. Ask internet provider to format item if it is not working through either a firmware update or the internet provider resetting the item to format to the customer's network connection.