An automated attendant system performs functions similar to a telephone receptionist, including routing calls to extensions, trying more than one extension, taking messages, etc. Auto attendant systems automatically connect an outside caller through a telephone company central office to an extension of a telephone switching system such as a private branch exchange (PBX), or key telephone system. In an auto attendant system, the auto attendant is interposed between the telephone central office serving the called party's business or institution and the switching system serving that same business or institution. The auto attendant system uses port circuits to connect the auto attendant to the switching system. In another auto attendant system, the auto attendant is not directly connected to the telephone company central office, but is connected only to station circuits of the switching system. The auto attendant depends on incoming calls being routed to it by a common PBX feature which requires that the auto attendant further use the switching system transfer capabilities in order to extend the call to the inside party selected by the outside party. The automated attendant system typically presents the caller with a menu of options and instructs the caller to depress particular keys on their telephone to select those options. For example, the auto attendant may instruct the caller to press "1" for sales, "2" for customer service, "3" to enter an extension, "0" to reach a live attendant (or operator). In response to the menu, the caller typically presses a key corresponding to the option desired, and the auto attendant performs that option. The auto attendant will connect the caller to a particular extension, or groups of extensions, will connect the caller to a voice mail system. Automated telephony attendant systems allow the caller to call and contact or leave a message for an employee at any time during the day without having to worry about the message not being received.

Automatic attendants are commonly being implemented in office type environments. Typically, these automatic attendants are using phonetic-based recognizers to perform call routing functions in conjunction with a private branch exchange (PBX). In auto attendant systems, communications from the system to the extension owner are via the telephone lines and are output to the extension owner by playing an audio message after the handset is lifted or a key is pressed, ringing the telephone, or illuminating a lamp. The owner communicates with the auto attendant system via the same telephone lines by lifting the handset, pressing one of the number keys or other specialized keys on the telephone unit, or hanging up the handset. Some auto attendant systems include a call holding feature which operates if the designated extension is busy. This feature gives the caller the option of being placed on hold and subsequently put through to the called party if the extension becomes available. The most common feature of auto attendant systems is call routing. When a call is received by the PBX, an auto attendant system answers and plays a message. When the requested information is entered, possibly after the caller listens to part or all of a directory, the call processor forwards the call to the designated extension. In this case, the auto attendant is routing the call in place of a live operator.