- Comcast charges a $7 per month modem rental fee as of the date of publication. For many customers, the annual cost of $84 is justification for purchasing their own modem. According to a September 2009 article by DailyFinance, some modems made by Motorola and other manufacturers will cost about the same amount as a year of renting a modem from Comcast.
- As of the date of publication, Comcast uses a cable modem standard known as DOCSIS (Data Over Cable Service Interface Specification), which is the standard supported by most cable modems. The first three versions of DOCSIS (1.0, 1.1 and 2.0) supported maximum downstream speeds of about 40 megabits per second. DOCSIS 3.0, which is the newest technology introduced in 2006, supports “channel bonding,” in which multiple cable channels can be paired together to increase speeds. According to a January 2009 article by Ars Technica, Comcast in 2008 began offering 50 Mbps download speeds to its customers thanks to the DOCSIS 3.0 modem technology.
- Comcast’s website provides a list of supported devices that use the DOCSIS technology standard. Not all modems will work with every Internet service Comcast offers. As of the date of publication, there are eight tiers of Internet services for residential customers: “Economy,” “Economy Plus,” “Performance Starter,” “Performance,” “Blast,” “Ultra,” “Extreme 50,” and “Extreme 105.” Customers can use any DOCSIS modem on Comcast’s list of approved modems for any of the Internet tiers, except for the “Ultra,” and “Extreme 50,” tiers. Those services require a modem that uses the more advanced DOCSIS 3.0 technology. Comcast customers who want a DOCSIS 3.0 modem can consider the Motorola Surfboard SB6120 Cable Modem, Netgear DOCSIS 3.0 Cable Modem CMD31T, or the Arris Touchstone Cable Modem WBM760A. Customers who want to try a lower-tier Internet service from Comcast can use the Arris Touchstone Telephony Modem TM602G (DOCSIS 2.0), or the Motorola Surfboard SB5100 Cable Modem (DOCSIS 2.0).
- In some cases, Comcast customers may be using a modem that’s known as an “end of life device.” These are devices that have reached the end of their life cycle and should be replaced. They may not support the higher Internet speeds that Comcast’s services offer. While these modems may still work on the Comcast network, Comcast recommends that they be replaced. For example, according to Comcast’s website, DOCSIS 1.0 modems will not be able to work on the Comcast network as of December 2011. Customers with end of life devices can purchase a new modem or lease one from Comcast.