All predictive dialers work along comparable standards, but the structural design by which dialing is carried out can differ very much between companies. There are two basic kinds of predictive dialers:

Soft Dialers

Solutions that are software only use ISDN messaging, or a CTI link to supply call progress analysis for calls dialed. Software only dialers are frequently less expensive because they do not command costly telephony components, but in some cases can present a smaller amount of functionality than more customary "hard dialer" solutions, especially when it comes to sensing answering machines. A software dialer is usually connected to a vacant PBX system by the PBX CTI link. In quite a few cases a specialized "call classification" card is put into the PBX to execute call progress analysis, and answering machine detection.

Pros:

• Low cost, fewer components in overall solution
• Accommodating structural design works well in multi-site and distributed environments

Cons:

• Depends on the answering machine detection and call progress detection qualifications of the basic PBX/switch platform
• Numerous PBX's will not work with a soft dialer design
• Dependence on the CTI link of PBX means that if the PBX is improved or altered, the predictive dialer will predictably need improved or altered also to make sure that it is correctly certified for the proper CTI link version

Hard Dialers

Hardware dialers use dedicated telephony switches to carry out call progress analysis and answering machine detection. Those switches typically have 2 key kinds of connections, agent audio and external audio. The agent audio connections are typically basic T1/E1/ISDN etc. telephony durations that is connected right to an existing PBX (although other connection kinds that do not call for a PBX are available such as Analogue or VoIP connections). When a representative first logs in for the day the dialer will make a call from the switch straight to the phone on the representative's desk. This open phone call between the representative and the dialer switch is kept open from then on for the rest of the session. The next kind of connection is the external audio connection which is the