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SURFBOARD SB2100D EXTERNAL CABLE MODEM
Last updated: 9/2/01

The SB2100D is controlled through a series of Browser (IE, Netscape, etc.) windows.  During normal installation the ISP' s tech usually sets the Home page to the local network address of the CM dial-up menu: http://192.168.100.1/phone.html on my system.  That is, the CM behaves like a mini-web server when viewed by the browser.  Other menus/web pages (and some meandering) are:

Diagnostic.  Available only to ISP techs (I didn't see it and haven't figured-out how to get at it).

Help.

Startup - shows the sequence of steps the MODEM goes through when starting-up.

Signal - CM cable frequency, max bit rate (mine is 512K), etc., and MODEM status if your cable system is one-way and the CM has connected via phone line for data going up stream.

Addresses - Shows the address network addresses used by the CM and the maximum number of CPE MAC Addresses.  Mine is set to 1.  Each and every Ethernet adapter on this planet is assigned a unique CPE MAC address.   Let me say it again...  When you buy an Ethernet adapter it has a CPE MAC address which uniquely identifies it.  The CPE MAC address can be read over the network.  When the CM is installed, it reads the CPE MAC address from the adapter to which it is connected and marries itself to that adapter.  From then on, it will not work with (send packets to and receive packets from) any other adapter (unless there is way to forge CPE MAC addresses).

According to the User Manual, the ISP can configure the MODEM for Multiple users on a LAN connected together with an Ethernet hub.  I presume that would amount to increasing the maximum number of CPE MAC addresses the CM can learn and marry with (becomes a bigamist).  I have operated the CM through an Ethernet hub, but it still will only talk with the Ethernet card in my machine.

The CM connects to a PC with a straight-thru cable (I received one that wasn't made correctly, but works) and has to be connected to a normal hub port with a crossover cable.  The crossover function is performed in the CM.

All in all this MODEM works well.   If you are on a one-way cable system it connects with it's internal dial-up 33.6 MODEM, sends data upstream via the phone line, and receives data downstream via the cable.   If you have your computer booted-up to windows, it usually, automatically dials-up the network when you turn- on the CM power switch  and  connects pretty fast for a dial-up.  Although I would prefer a 56K MODEM for the upstream leg (and better yet a two-way cable), 33.6K is ok most of the time because upstream data is usually nothing more than keystrokes and other stuff at low data rates.  I really miss the 56K connection, however, when uploading my web site.

Of course, if you are on a two-way cable system, the MODEM is configured by the ISP to omit the dial-up, goes both ways on the cable, and, as I understand it, is always available or connects almost instantly.

My only real gripe is that cable system drops the connection more than I would like to see and there is absolutely no indication from the CM or its Browser Interface that the connection is no longer there.  The only way to know if the cable is really gone is to browse around and receive nothing but can't connects.  If one tries to redial, the CM says it's already connected.  So, you have to tell it to hang-up MODEM, wait for it to shut-down the ( dropped) connection, and then tell it to dial MODEM.  There is no dial-up icon on the tool bar which disappears when the connection is dropped.  On the other hand, if you have to reboot your computer or have computer hiccup, when you are connected to the Internet, you will usually find your computer is still connected to the Internet when Windows comes back up.

One major advantage with this external CM/dial-up MODEM, as compared to an internal CM and separate dial-up MODEM combination, used in a one-way cable system, is that should be possible to share an Internet connection with other computers on a LAN with a broadband router or software such as Windows 98 Second Edition ICS.

Larry

9/2/01 Update.  On 8/21/01 our cable system was upgraded to 2-way operation.  You can read about it here.

Specifications, etc.

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