3Com cable modems / Mediaone

[signal11 () MEDIAONE NET (Signal 11)]

I'm not certain this is the appropriate forum to discuss this,
however I've been unable to locate any documentation about this
on 3Com's website nor has technical support been helpful in
enlightening me (I have called their 800 number).

The 3Com external cablemodem (CMX) allows the upstream provider
to download firmware updates into your cablemodem.  This can
(and I suspect usually is) done without the user's knowledge,
and it took some digging to uncover this "feature".  The cable-
modem can also be reprogrammed via a serial port in back,
although my attempts to access it have proven futile.
I am also very curious to find out how to telnet into this thing,
as there are references to it being "password protected"
to prevent intruders.  Somehow I rather doubt mine was
given a password (and thus open to the whole world).

I'm very much concerned about using a device, which has
little/no technical specifications, with my system.
Can firmware be uploaded by anyone?  How does the modem
authenticate the head-end system?  Does anyone have any
information on how to reprogram this modem?


--
Signal 11, BOFH to the UF list and malign.net
Where's the DIR command?