Dial-up connections

Dial-up lines are local loop public Switched Telephone Network (PSTN) connections that use modems, existing phone lines, and existing long-distance carrier services to provide low-cost, low-bandwidth WAN connectivity and remote network access. Dial-up lines are generally limited to 56Kbps, and are sometimes used for backups for higher-bandwidth WAN services.

Dial-up Hardware
You can keep hardware requirements simple and use a modem attached to a serial port on a PC, or you can use a specialized modem card installed in the server to support multiple phone connections.

RJ-11 Connectors

RJ-11 connectors are four- or six – wire connectors that are used to connect telephones and modems to telephone outlets. The RJ-11 connector looks much like the RJ-45 connector that is used to connect network cards to LANs. When you are looking at an RJ-11 and RJ-45 connector, the RJ-11 connector is smaller.

 

Benefits and Drawbacks of Dial-up

Dial-up lines have two major drawbacks: they are slow and they can have considerable connection wait time (because the modem has to dial and establish a connection before data can be sent across the network). Despite those limitations, dial-ups are popular because they provide enough bandwidth to get the job done at a very low cost, and because the telephone infrastructure is already in place and is universally available.