Questions About Cable

[adam1504]

I currently have Comcast@Home cable modem service and I have a few questions about cable in general.

1) If my RF is not the greatest in the world but the modem still connects and works fine, does that affect my speed?
2) I know as more users go on, the more the speed is affected but does that mean just having their computers connected to @Home affects the speed or only if they are actively using the connection and downloading.
3) I live a high-density area where many people will probably be finding out that cable Internet is available. (Where I live the entire neighborhood is outside the available distance for DSL, our dial-up modems don't even get 26.4bps the line quality and distance is so poor!) Will Comcast@Home place any guarantees on the speed of the service?
4) Comcast recently upgraded to fiber-optic lines in the area to be able to offer digital cable to customers. Does upgrading to fiber-optic lines do anything for cable modem users?

Those are all of my questions. Thanks for the help.

Adam

[Kip Patterson]

As long as your upstream and downstream signals are consistently within the specified levels the speed will not be affected. If you are near one of the extremes, then the usual variations in the signal level will cause retransmissions, etc.

Only active computers use resouces.

Comcast will not make any meaningful speed guarantees. Some providers say "faster than ISDN", but the reality is that the speeds can vary during the day if the ISP is overloaded at any point. These overloads usually are upstream in the system. Most local circuits do not get overloaded because of the number of users in your neighborhood, but it can happen and will happen more often in the future.

The installation of fiber means that you now have nodes where the signals are converted from optical to electrical and vice versa. The cable modem operates in the same manner in either environment. The change to fiber means better signal to noise ratios, and less ingress, which will help both modem and TV service.

At the present time, until HDTV replaces NTSC and the cable systems no longer have to carry both analog and digital TV channels, the downstream bandwidth to a node (or group of nodes if they are combined at the headend) is usually limited to what one TV channel will carry - channels are in short supply. The limitation on the upstream bandwidth is even worse since the frequency band for upstream is pretty narrow.

Kip