The function of the private line eliminates the possibility of someone other than you reviewing your call details, from phone sets, which have the shared extension, additionally no one can monitor your call or connect to you call.
Digium Wildcard TDM410 is a half-length PCI 2.2 compatible card that supports FXS and FXO interfaces for connecting analog telephones and lines through a PC, it was developed as a replacement for TDM400P. By using IP-PBX Asterisk Open Source software and a standard PC, the user of Digium Wildcard TDM410 could build a small office telephone system, which will have all of the sophisticated and useful features of modern telecommunications equipment for big business.