Can your PC replace your telephone and fax machine?
Telephones are a classic example of the general-purpose PC versus the special-purpose appliance. When looked at in this light, the telephone is a surprisingly heavyweight appliance, basically needing its own network...
With the advanced Call Transfer capabilities PC-Telephone can also be used as a telephone exchange (PBX) or gateway between different communications networks - Internet/Intranet and ISDN/PSTN.
The picture below shows the possible PC-Telephone connections: