In today's world the telephone has become the most essential medium of communication. Telephones are widely used all over the world mainly for domestic use or may be for office use. In case of Office Phone Systems, the system is so designed that it allows its user to share the same external telephone lines rather than using individual telephones. These telephone systems are mainly designed for several phone users at a single location. By using these types of phone systems lots of money can be saved as it is very cost effective in comparison to any other phone systems.

The Private Branch Exchange or the PBX phone systems are telephone systems which are created specifically for business purposes in offices. This private branch exchange for Office Phone Systems is created mainly to form a private network between all the users, those who share the selected external telephone lines. This type of office phone systems is ideal for large and medium sized organizations or companies. These phone systems are very cost efficient as they allow sharing a few external lines among the users rather than having individual users use their own external lines. By using a PBX phone system it is very easy to reach someone within the phone system by dialing only a three or four digit extension. In PBX phone system there is some additional features like voicemail with forwarding, reminders, screen display and screen call options. The private branch exchanges for office phone systems are also capable of answering the phones and greet their clients with auto-generated messages and there is also an option for live call transferring in this system.

The Automated Attendant is a phone system accessory that can answer the phone calls by generating automatic messages electronically. The callers are allowed to route themselves through a series of menu prompts by the Automated Attendant. The voice mail systems are generally equipped with the basic automated attendant system. An ACD or Automated Call Distributor is a phone system accessory which helps to route incoming calls among a set of extensions and handles them efficiently. ACDs are mainly used in call centers or enquiry offices where it can process many incoming calls at a same time. The CTIs or the Computer Telephony Integration have broad category of applications. The CTIs are used to connect a phone system to a computer. The CTI retrieves important data from any incoming call and with their expertise and process this data for useful business purposes. The Key System Unit (or KSU) have features like call forwarding, extension dialing and voice mail options. The Voice Over Internet Protocol or VoIP helps users to place voice information in digital form using the Internet.

The office telephone systems are integrated with standard analog telephones, fax machines, cordless and cellular phones with the traditional telephone network and also have the option for the Internet by Voice over IP. The office phone systems have become very popular as they can deliver an easy configurability connection with unprecedented prices.