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.
...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.
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.
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
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.
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.
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
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.
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.)
brings us to do the other interesting aspect—What's
Linksys puts a sticker on the bottom of their cable modems and routers warning you that tampering with the insides voids the warranty.
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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