A cable modem connects your computer to the cable company using the same coxial cable as cable tv, you connect hubs, switches etc to this modem so multiple computers can use the net at the same time.
DSL modem and filters
A filter stops the computer cutting out the phone or vice versa
A typical ISDN connection
carries voice, video etc
Uses satellite for two way communication, download speeds are up to 500Kbps, uploads are closer to 56Kbps, used by people in rural areas.
Voice over IP (VolP)
Telephone over an internet connection, cheaper, like skype