Cable Modem Mania!

Many people have asked about my cable modem service, so I thought I'd write up a brief summary of the service, the modem, and the speed.

What is a cable modem?

Well, I'm no engineer, but I'll make it simple. Telephone lines don't have a lot of bandwidth. That is, the "pipe" isn't very wide, so not a lot of water can go through. However, our cable modem service uses the standard coaxial television cable lines, which is fiber optic from the box outside to the main server at the cable company. From there, it's straight onto the Net. This is a bit oversimplified, but it's pretty much correct.

Why do I want one?

The fastest modem you can buy right now is about 56,000bps -- well, sort of. This is only one direction, and isn't widely used at all. However, cable modems can travel well over 10 megabits-- that's 10,000,000 bps! (correct me if I'm wrong). The pipe is much wider, and the water just comes pouring through. However, don't expect that you'll actually be going that fast. Read on to find out how fast it really is.

Who makes your cable modem?

The cable modem is a CyberSURFR, made by the fine folks at Motorola. It's really cool looking, like a wave is about to break on the front (see picture). It has four lights on the front: Power, cable, PC, and test. You want the first three on.. the last one is supposed to be off.

So what are the stats? How fast DOES it really go?

This puppy can receive data at up to 10Mbps, and send data at 768kbps. It is encrypted with DES both directions, so nobody will be sniffing any packets of yours. IP addresses, at least on my system, seem static, though if you turn off the box you may lose it. You connect your computer (Mac or PC) to the modem via your standard 10Base-T ethernet connection. How fast does it go? Well, I've seen it go over 160kb/sec... web pages are usually 20-40 kb/sec... ftp downloads are often even faster!

UPDATE 5/14/97: Less than a month ago, Roadrunner added a few more T-1 lines... and as a result, things have gotten much faster. You still have bad days sometimes, but overall, performance is superb.

Who is providing your Cable modem service?

Southwestern Cable TV, a subsidiary of Time Warner Cable, provides it to us here in San Diego, under the name Roadrunner. There is lots of localized content (see picture) such as news, weather, things to do, etc.

Alright already! How much does it cost?

Installation of the modem costs $99 here in San Diego, for subscribes of Southwestern Cable. The monthly fee is $45. You get software, Internet Explorer 3.0, and several books which aren't that bad.

Update 5/14: I understand that Cox Cablevision will be introduced @Home very soon. It actually costs more to install ($150?) but less per month ($39). They are very, very similar systems.

Anything else cool about it?

Yes! You can hook it up through a Ethernet hub (like we do here) and have up to 6 people on one modem! We currently have three computers on the hub, and two are using the modem. You can set up subaccounts for the other computers so they get access too! They get email addresses, and access and all. If you only want to set up an email account, you can do that too- they can only send email, and they can't surf the web or the newsgroups. Update 5/14: Roadrunner now charges $5 per additional IP address, per month. Lame, lame, lame.

So what DON'T you like?

Update 5/14: Well, the Login program problems have been well documented on MacFixIt and elsewhere- it sucks. Time-Warner (actually Toshiba) is working on a new one, but I'd recommend Login Love from a fellow UCSD student, Eric Lundberg. The $5/IP charge is lame but by the time they actually start charging us I will no longer be a customer (i'm moving back home).

You now MUST use the proxy server... so I find myself reloading a lot..

There is no web page hosting, and we are still behind a firewall.. so you can't have a website on your own machine, as far as I know.

Reliability is much better than it used to be, which is a good thing actually.

Roadrunner is copyright Time Warner Inc. Picture is used without permission. Top picture of two modems is copyright Jeff Keller. Comments and questions may be sent to Jeff at jakeller@ucsd.edu. Last updated 5/14/97.