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Linksys BEFCMU10 Cable Modem Review

Notice: this product review is years old (its last update having been on October 13th, 2009 at 8:50 PM) at this point. Some cable networks have dropped support for older DOCSIS standards such as the one supported by this modem. This generally isn't something a firmware upgrade can fix (unless of course the modem's chipset had the needed functionality present but disabled or unsupported in older software releases). Even if your cable provider does still maintain support for older cable modems, your connection speed will be limited by using an older modem.

Cable Modems aren't normally very exciting things. Most people get them from their cable company, usually under some kind of rental arrangement or rarely even at no extra charge.

random BEFCMU10 picture cribbed from somewhere on the Internet

...You can also buy them and own a cable modem instead. And you may want to, because even low rental fees add up over time, and in a while, you could have purchased one with what you've paid in rental fees.

Of course, renting your cable modem does have its advantages. If your cable modem ever breaks, the cable company will probably just hand you a new one and send the broken one off to their magical factory to be repaired. If a cable modem you happen to own breaks, then tough luck. You have to buy another one or hope that it is under warranty. Sometimes you can make a repair, although the highly integrated nature of the modem's internals may rule out all but the simplest repairs. If the standards change and your modem is no longer supported, well, you're out of luck.

Cable modems aren't the kind of things that tend to break regularly, outside of catastrophic failures. They (should) just sit there and shuffle data from your computer to the Internet and back again. This is a job that they can do for years. Even when yours is hopelessly obsolete, it will probably still work just fine IF you can find something to connect it to. The cable standards haven't changed that much and established cable modem networks don't disappear overnight.

For the longest time, I did rent my cable modem from the cable company and it worked well enough. Every now and again, their Motorola Surfboard SB4100 would drop its connection and have to work at getting it back again. This didn't happen often enough for it to be annoying and I chalked it up to just “one of those things”. When you've been on a dial-up ISP long enough—especially if that dial-up ISP was the only service out there, and yet still not the fastest or most reliable—anything is an improvement.

That rented cable modem shuffled a lot of data in its time. It went under in a basement flood and emerged alive after some drying-out time. And it also became increasingly temperamental. What used to be about thirty seconds of no connectivity turned into several minutes, several hours and eventually days.I doubt that the flood had anything to do with this, as the modem worked fine for a long time afterwards before the malfunctions picked up.

The cable company (Mediacom in this case) had changed modem providers several times since I'd signed up with them. They went from using Motorola modems that worked well to RCA ones that also worked well. At some point, they started using Ambit modems that seemed to work fine if you didn't mind the fact that the Ethernet port on them was pretty well nonfunctional. (The USB port worked fine.) Today (August 2009), they seem to be handing out Arris modems.

In light of the fact that I needed a working Ethernet port (since my connection pours directly into a router that has only Ethernet ports), I decided to buy a cable modem of my own.

There are actually lots of cable modems to choose from on the market. I finally settled on the Linksys BEFCMU10 modem, as it seemed to have the simplest, least flashy design. And while I don't generally recommend the Linksys wireless routers, the modem's design does let you stack it with a wired or wireless Linksys router.

Setup is a breeze. There isn't much you have to do, and if you can connect three cables to a box with clearly marked, very different connectors, you too can install the Linksys BEFCMU10. The worst part—in my experience—was calling the cable company. It's very likely that you will have to register your new cable modem before you can use it, and this requires a call to the cable company. When you call, have your modem handy as you will need to read the modem's MAC address to the support rep when they answer. I was on hold for about a million years as I made the mistake of underestimating the sheer number of people who become unhappy when they cannot watch pay-per-view wrestling. I have nothing witty or sarcastic to say here.

And that's it. Once the MAC address of your new modem has been registered, you should be off and running.

There is no software or driver to install as long as you are using the Ethernet connectivity provided with the BEFCMU10. (USB users will have to install a driver, this makes the BEFCMU10 show up as a virtual Ethernet adapter when it is attached to your computer.)

So what else is there to explore?

In the case of the BEFCMU10, not a whole lot.

Nearly all cable modems have a built in web page where you can do some basic administrative tasks and view a log of the modem's activities. The cable company actually has control over all of the fun stuff, all you can usually do is reboot the modem, view a log of its activities and see some real-time statistics concerning your connection.

Most cable modems will respond with something if you hit this IP address. (Note: don't click that link if you don't own the cable modem in question, or aren't sure if the owner might not be happy if you were to look at his or her cable modem statistics page.

Linksys doesn't even give you that much. The web interface of the BEFCMU10 is austere. It is subdivided into three pages with information about the modem, information about your connection and a 50-event log that you can clear.

That is all.

You cannot reboot the modem from the web interface. And that's not a huge loss, as cable modems don't require such maintenance very often. (If yours does, there's probably something wrong with its software, hardware or the line it is communicating over that is confusing the heck out of it and causing it to lock up.) It would just be nice to have the capability of performing a remote boot if your modem is located somewhere inconvenient or you are three stories away from it.

Curiously, given the austerity of its built in web pages, the BEFCMU10 does obtain the time and date from your cable provider and will at least time stamp the entries in its log. The first few always seem to bear a January 1970 date, but that's not too surprising considering that there is no built in real-time clock or backup battery.

The BEFCMU10 appears to run a very stripped down version of Linux. (Because people have asked, this is mostly educated guessing. I haven't actually dumped the firmware. Broadcom's documentation in particular indicates that a Linux based firmware implementation is what they would recommend. Identification strings returned by the built in web server also strongly suggested a Linux-backed firmware implementation.)

Which brings us to do the other interesting aspect—What's Inside

Linksys puts a sticker on the bottom of their cable modems and routers warning you that tampering with the insides voids the warranty.

BEFCMU10 Insides Small

Oh well.

Behold, the insides of one Linksys BEFCMU10 cable modem, carefully presented on one ESD handling regulation compliant twin bed.

There isn't much to speak of inside. Looking at the main board reveals a smattering of components, including some RAM, a flashable ROM, the cable tuner module and a few Ethernet support components.

The heart of the BEFCMU10 is a Broadcom QAMLink BCM3349KPBG single-chip cable modem. It has a 200MHz 32-bit MIPS processor core built in.

Notice the "artistic" Bel logo that's part of the coaxial connector. A few of the front panel LEDs are also multi-color units. Not much is said about these in the documentation, but if they come on, your cable modem has had "a bad day".

I'm not sure how hackable this thing is, as I'm sure that both Linksys and the cable companies have put some roadblocks in the way to stop people from doing things they should not be doing with the public cable TV network. Cable modems typically download their operating parameters (and in some cases, firmware updates) over TFTP. Early units would look for a source of instructions via TFTP on any of their network interfaces. From what I've read this seems not to be possible with the BEFCMU10.


Linksys has a heck of a great product here in the BEFCMU10. It's reliable, reasonably priced (there isn't much price competition in cable modems—they all cost about $80 US) and drop-dead easy to set up. You really can't go wrong with it, as long as your cable provider supports and allows the use of your own cable modem.

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Copyright 2009-2016 William R. Walsh. Some Rights Reserved. Written 08/24/2009. Updated 10/10/2009, 05/09/2016. Permission is granted to mirror this page in its unedit entirety as long as a link back to this site and credit for the material is provided. You may not charge a fee or exchange items of value to provide access to this page or its content, other than an amount reasonably necessary to cover the cost of connection time, data transfer or printing supplies. Content from this page may not be displayed alongside advertising content of any type. You may use portions of this page in other products only if you provide credit and a link back to this page and only if the finished product is freely accessible to anyone interested in having a copy. If you use this material in work of your own, you may not charge or exchange items of value to provide access (other than as reasonably necessary to cover connection time, data transfer fees, or to cover printing supply costs) nor may you display advertising materials alongside any content you use from this page. Images may not be edited other than to resize them or to provide for faster downloading.