The advantage of this type of service is its wide availabilty and cost.
The disadvantages are slow speed and, unless you are using a dedicated telephone line, calls could be missed while connected to the Internet. Because of this problem, there is an added cost if you opt for a dedicated line.
DSL (Digital Subscriber Line) modem uses your regular telephone line and provides fast Internet access. Connection is 'Always On'.
The advantage of this type of modem is being able to use your telephone while being connected to the Internet; hence, there is no need for a dedicated line. This is possible because this technology is not only limited to voiceband audio frequencies and uses coded orthoganal frequency division modulation (DMT) which enables multiple bands of frequencies on the same telephone line.
DSL is still not available everywhere.
This connection, like the DSL, is extremely fast but does not use a telephone line. Connection is provided through your Cable TV company and is 'Always On'.
Cable modems use the range of frequencies that were intended for RF television channels. This principle uses multiple cable modems connected to a main cable from the signal source on the same frequency band.
A low-level media access protocol enables multiple modems to function together on the same channel. Frequency division multiple access keeps the up and down signals separate.
In comparison to dial-up modems, Broadband modems are more advanced because they are capable of modulating/demodulating hundreds of channels at the same time.