System Features

Account Codes

This feature allows a station user to input a multiple digit code for certain types of outgoing trunk calls. Each code is associated with a unique file record, usually used for account billing purposes.

Answer Detection

This feature detects the state of outgoing trunk calls that do not receive network answer supervision to improve the accuracy of the call duration field in CDRs.

Authorization Codes

This feature allows a station user to input a personal identification code as a means for extending the control of system users’ calling privileges and security for remote access callers. Authorization codes may be used for any or all of the following reasons: allow a calling user to override the FRL assigned to the originating station or trunk, restrict individual incoming tie trunks and remote access trunks from accessing an outgoing trunk, identify certain calls on CDRs for cost-allocation purposes, and provide additional security control for the system.

Automated Attendant

This feature allows the system to answer incoming trunk calls with no intervention of an attendant position. The system will provide the caller with a message or dial tone and allow the caller to directly dial an internal extension number.

Automatic Alternate Routing

This feature provides alternative routing choices for private on-network calls. When implemented, the system automatically selects the most desirable (normally the least expensive) route among multiple trunking facilities for private network calls. AAR also provides digit modification to allow on-network calls to route through the public network when an on-network route is not available.

Automatic Call Distribution

This feature provides the automatic connection of incoming calls to specific splits (hunt groups) of station users (agents). Calls to a specific split are automatically distributed among the agents assigned to that split. If agents are not available, the call can queue to the split to wait for an agent to become available.

Automatic Camp-on

When a DID call has been terminated at a busy station, the call is “camped-on” to the called station. When busy station becomes idle, it is automatically connected to the camped-on incoming trunk call.

Automatic Circuit Assurance

This feature assists users in identifying possible trunk malfunctions. The system maintains a record of the performance of individual trunks relative to short and long holding-time calls. The system automatically initiates a referral call to an attendant or display-equipped voice terminal user when a possible failure is detected.

Automatic Number Identification

This feature allows the system to receive an incoming caller’s local telephone company trunk billing number and display the number on a station user’s voice terminal with a display. The ANI is transmitted over an incoming digital trunk circuit with the use of in-band or out-of-band signaling techniques.

Automatic Recall

This feature alerts a voice terminal after a fixed interval that a call it transferred has been placed on hold, is camped-on, or continues ringing with no answer.

Automatic Route Selection

This feature routes calls over the public network based on the preferred (normally the least expensive) route available at the time the call is placed. ARS provides a choice of routes for any given public network call. The following types of trunk groups can be accessed by ARS: local CO, FX, WATS, tie trunk, T1/E1, ISDN PRI, and IP WAN. The system selects the most preferred (normally least expensive) route for the call. Interexchange carrier code dialing is not required on routes selected by the system. Interexchange carrier codes are assigned in translations to best benefit the customer on any given call. These codes are inserted as needed to guarantee automatic carrier selection.

Automatic Transmission Measurement System

This feature provides for trunk facilities to be measured for satisfactory transmission performance. The performance of the trunks are evaluated according to measurements produced by a series of analog tests and are compared against user-defined threshold values.

Call Coverage (Multiple Call Forwarding, Split Call Forwarding)

This feature provides automatic redirection of calls that meet specified criteria to alternate answering positions in a call coverage path. Lead coverage paths can be administered to apply to all calls all the time, internal or external calls, or to apply to a specific day of the week or a specific time of the day. Different coverage paths are administered based on incoming call origination, type, or time.

Call-by-Call Service Selection

This feature allows a single ISDN-PRI trunk group to carry calls to many services or facilities or to carry calls using different interexchange carriers. The feature typically uses the same routing tables and routing preferences that are used by AAR and ARS. The service or facility used on an outgoing CBCSS call is determined by information assigned in the AAR/ARS routing patterns. Without CBCSS each trunk group must be dedicated to a specific service or facility. CBCSS eliminates this requirement by allowing a variety of services to use a single trunk group. These services are specified on a call-by-call basis.

Call Detail Recording

This feature records detailed call information on all incoming and outgoing calls on specified trunk groups and extensions administered for intraswitch recording and sends this information to a CDR output device. The CDR output device provides a detailed printout that can be used by the system administrator to compute call costs, allocate charges, analyze calling patterns, detect unauthorized calls, and keep track of unnecessary calls.

Call Log

This feature stores dialed station numbers and incoming identification numbers (internal CLID, CLASS CLID, ANI) at a multiple line voice terminal with a display. The numbers that are stored are those of the most recently dialed and incoming calls. There is a limited amount of stored and displayed numbers that varies by system. Pressing a call log button brings up the display. Calls to numbers appearing in the call log display field can be dialed automatically through menu control keys.

Centralized Attendant Service

This feature allows services performed by attendants in a private network of switching systems to be concentrated at a central, or main, location. Although all incoming calls to the network are routed to a main PBX system, each branch in the centralized attendant service configuration has its own listed directory number or other type of access from the public network. Incoming trunk calls to the branch and attendant-seeking voice terminal calls are routed to the centralized attendants over a release link trunk. The centralized attendants are located at the main location.

Class of Restriction

This feature defines different classes of call origination and termination privileges. Systems may have one restriction class, one with no restrictions, or as many restriction classes as necessary to effect the desired restrictions.

Class of Service

This feature determines whether or not voice terminal users can access any or all station or system features and functions. There are many COS levels that can be programmed by the system administrator; each level is associated with a defined feature/function set that may contain one or many features and functions. Each COS level allows or denies access to the defined feature/function set. Every system user is assigned a COS level by the system administrator.

Controlled Private Calls

This feature allows the system operator to charge station users for personal outgoing calls. The following items define station users: extension number (virtual or real), personal identification number, and call restriction table for private calls. The user can make a private call according to the following rules: only from his own set, from every authorized set in the subnetwork, or from only a few selected sets.

Delayed Ringing

This feature allows trunks and station lines to ring immediately at the dialed destination station and, after a programmed interval, at a secondary station that shares the same line appearance as the original destination station.

Dial Plan

The dial plan is the system’s guide to digit translation. When a digit is dialed, the system must know what to expect based on that digit. The dial plan, or first-digit and second-digit tables, established during administration for each system provides information to the switch on what to do with dialed digits. The tables define the intended use of a code beginning with a specific first digit or specific pair of digits. These digits tell the system how many digits to collect before processing the full digit string.

Dialed Number Identification Service

This feature provides a display of the listed directory number of an incoming trunk call to the attendant position. The display can be the actual digits of the number, or an alphanumeric name or identifier. This screening feature allows an attendant to better handle the incoming call and provides a higher level of customer service.

Direct Department Calling

This feature allows direct inward access to an answering group other than the attendant even if the system does not use the DID feature. A direct department answering group can consist of voice terminals and individual attendants. One extension number is assigned to all voice terminals and individual attendants. Incoming calls to a direct department group can be internal or external. With this feature, an incoming call rings the first available voice terminal or individual attendant in the administered sequence. If the first group member in the sequence is active on a call (busy) or has had calls temporarily redirected, the call routes to the next group member, and so on. Incoming calls always try to complete at the first group member in the administered sequence. Calls are not evenly distributed among the group members.

Direct Inward Dialing

DID connects calls from the public network directly to a dialed extension number without attendant assistance. Specialized DID trunk circuits are required to implement this feature. DID reduces attendant workload and facilitates connections between an external calling and an internal called party.

DID Call Waiting

This feature allows an incoming call on a DID trunk circuit to be automatically camped-on to the destination station if the destination station is busy.

Direct Inward System Access

DISA allows system users who are off-premise to dial into the system, input a special access code, and use the system facilities even though the caller is not using an internal voice terminal. It allows access to the system’s optimally priced trunk network facilities and other cost savings features.

Direct Inward Termination

This feature automatically routes incoming network exchange calls to a preselected station without attendant assistance. The called party can process the call in a manner similar to any normal trunk call.

Direct Outward Dialing

This feature allows voice terminal users to access the public network without attendant assistance. Station users dial a defined trunk access code (such as 9) for public network connection and dialing.

Extended Trunk Access

This software feature provides a means for routing calls that are not defined in the first- or second-digit tables or the feature/trunk access code tables. This feature makes use of an extended trunk access routing pattern or node number for determining how to route an unidentified call.

Facility Restriction Levels

FRLs provide multiple levels of restriction for users of the AAR or ARS features. FRLs provide a method of allowing certain calls to specific users and denying the same calls to other users. For example, certain users may be allowed to use CO trunks to other corporate locations, whereas other users may be restricted to the less expensive private network lines. The FRLs are defined and programmed into the system by the administrator and are transparent to the station user. Regular dialing procedures are unaffected.

Facility Test Calls

This feature allows a voice terminal user to make test calls to access specific trunks, DTMF receivers, time slots, and system tones. The test call makes sure the facility is operating properly. The feature is implemented by dialing an access code.

Forced Account Code

This feature forces a station user to enter an account code for all outgoing trunk calls. The account code must be entered before dialing the outgoing number. Calls are processed only after the account code is entered and verified. Some systems allow calls to be classified into multiple groups, such as: call with a controlled project number, call with an uncontrolled project number, and call without a project number. The choice of call depends on a data system configuration based on two parameters: with/without a project number or with/without a controlled project number.

Hoteling

This feature allows users whose stations are translated to their own preferences and permissions to associate those preferences and permissions with any compatible terminal. These include the definitions of terminal buttons, abbreviated dial lists, and COS and restriction class permissions assigned to the user’s station.

House Phone

This feature allows station users to use selected voice terminals to reach an attendant by simply going off-hook.

Hunting

This feature routes calls to a station within a predefined ordered group after checking for station idle or busy status. Calls are routed to another group when all stations are busy. Hunting is accomplished through the ACD, direct department calling, and UCD features. The order of hunting is defined under each feature. Under direct department calling, call distribution is not uniform across hunt group members.

Integrated Directory

This feature allows internal system users with display-equipped terminals to access the system database, use the touch-tone buttons to key in a name, and retrieve an extension number from the system directory. The directory contains an alphanumeric listing of the names and extension numbers assigned to all voice terminals administered in the system.

Modem Pooling

This feature allows switched connections between digital data endpoints (data modules) and analog data endpoints and data modems. The analog data endpoint can be a trunk or a line circuit.

Multiple Listed Directory Numbers

This feature allows a publicly published number for each incoming and two-way (incoming side) FX and local CO trunk group assigned to the system. This feature also allows DID numbers to be treated as listed directory numbers.

Music on Hold

This feature plays music for a caller who is on hold, waiting in a queue, or on a trunk call in the process of being transferred. The feature provides a means to let callers know they are still connected to the system.

Night Service

This feature directs all calls for the primary and daytime attendant consoles to a night console. It is typically activated when an attendant presses the night button on the principal attendant console and deactivated by pressing the night button again. Night service also can be activated and deactivated from one station in the system by use of a night service button assigned to that station.

Off-Hook Alarm

This feature allows a station user to call an attendant or any preselected programmed station by simply staying off-hook for a preprogrammed period. The calling number is automatically displayed at the attendant console or the preselected station.

Off-Premises Station

The feature allows a voice terminal outside the switching system location to be connected to the system via specialized CO trunk circuits. The voice terminal must be analog and must be registered with the Federal Communications Commission.

Open System Speed Dial

A station user can select a system speed number by dialing a system speed code or name and then dialing the relevant final sequence of numbers to select the external party.

Power Failure Transfer

This feature provides service to and from the local telephony company to a designated station during power failures affecting the PBX system. During PFT mode, no other system features can be activated.

Property Management System Interface

PMS interface provides a communications link between the system and a customer-owned PMS. The PMS allows a customer to control certain features used in hospital-type and hotel/motel-type environments. The communications link allows the PMS to interrogate the system and allows information to be passed between the system and the PMS.

Recent Change History

This feature allows system administrators to view or print a history report of the most recent administration and maintenance changes. The history report also lists each time a user logs in or off the system. This report may be used for diagnostic, information, or security purposes.

Restricted Incoming Station

When a station is configured to receive only incoming calls, the station user receives a busy signal as soon as the handset is picked up.

Restriction—Controlled, Inward/Outward, Toll/Code, Trunk, Voice Terminal

A series of features that allows an administrator or attendant to activate or deactivate defined trunk access and I/O calling privileges for a station or group of stations.

Route Advance

This feature automatically routes outgoing trunk calls over alternate facilities when the first choice trunk group is busy. This feature is implemented only if a station user selects the first choice trunk group with a dial access code. The system advances through a series of alternate trunk groups only if the first-choice trunk group is busy.

Shared Tenant Service

A system manager can partition the PBX to provide telecommunications services to multiple tenant groups. The tenant groups can have independent dial plans, CDR, ARS and call routing tables, attendant groups, and COS/class restriction levels. Each group is logically partitioned from the others for all premises telecommunications services. The number of partitioned tenants depends on the system.

System Speed Dial

A station user can call a number by dialing system speed codes or names. The list of system speed codes can be common to all system users or split into different lists. With splits, the users can access different lists according to their COSs. Each outside system speed code corresponds to the access feature code of a trunk group or external trunk (public or private).

Timed Reminder

This feature allows the system to be programmed to automatically call stations at specified times. When the called party answers, the station is connected to a recorded announcement or music source.

Trunk Answer Any Station

This feature allows any station to answer an incoming call trunk when the system is in night service mode. A common alert signal is sent to all stations, and any station can answer the call. The answering station can extend the call to any other station by using call transfer.

Trunk Callback Queuing

This feature places outgoing calls in an ordered queue (first in, first out) when all trunks are busy. The voice terminal user is automatically called back when a trunk becomes available. The voice terminal receives a distinctive three-burst alerting signal when called back.

Uniform Call Distribution

This feature allows direct inward access to an answering group other than the attendant. A UCD answering group can consist of voice terminals and individual attendants. One extension number is assigned to all voice terminals and individual attendants. Incoming calls to a UCD group can be internal or external. With UCD, an incoming call rings the member of the group that has not received a UCD group call for the longest period (the most idle member). Incoming calls to a UCD group extension number are distributed evenly across the group members.

Uniform Dial Plan

A UDP may be established during administration as part of the dial plan. This plan provides a common extension number plan that can be shared across a group of switches. If a UDP is to be established, all extension numbers (in the UDP numbering plan) must be the same length.

Virtual Extensions

This feature permits the assignment of circuits that do not physically exist, to be used for secondary extensions on multiple line voice terminals.

Voice Message System Interface

This feature provides a signaling interface between a PBX and an external VMS. The interface allows the VMS to activate message waiting indicators on PBX voice terminals.

Data Communications | Features/Function Enhancements

Digital PBXs were supposed to be the enterprise data communications network backbone, but some things were not meant to be. The first PBX data communications options were introduced in the early 1980s. In 1980 Intecom was the first to offer a high-speed data module capable of transmission rates of up to 57.6 Kbps. This was at the time when most modems were operating below 9.6 Kbps, and 10-Mbps Ethernet was not yet introduced. After the Intecom announcement, most of the older PBX suppliers announced data module options for their systems with maximum transmission rates ranging from 9.6 to 64 Kbps (Figure 1).


Figure 1: Call center configuration.

Data communications options were available for integrated voice/data or stand-alone data ports. The integrated voice/data port option required a data module that attached to a digital telephone and provided a RS-232C or RS-449 interface for an adjunct data terminal. Asynchronous and synchronous interfaces were usually available from each PBX suppler. Stand-alone data modules were also available and may have required a port circuit card dedicated to data-only communications. The early data modules were priced at about $300 to $500 and required the more expensive digital telephones to work. Most PBX systems at the time were not designed to handle long call holding times and required extensive traffic engineering to support significant customer data requirements. When digital trunks were first available in the mid1980s, the tariffs were very high, and the PBX digital trunk interface cards were expensive compared with analog trunk interfaces. The cost of LAN equipment, at first significantly more expensive than PBX data option pricing, declined rapidly during the 1980s, making it a far more attractive data networking solution than a PBX. PBX data modules, once considered a high-speed option, were viewed as slow when compared with LAN transmission rates. Dreams of the PBX becoming the data networking solution died by the late 1980s when LAN technology matured and network routers first entered the market. Shipment levels of PBX data stations (integrated and stand-alone) never exceeded 3 percent of total annual shipments.

PBXs attempted to make a comeback in the early 1990s by offering a wideband data communications option using an ISDN primary rate interface (PRI) circuit card. By bonding multiple B channels together, a PBX could support transmission rates up to 1.5 Mbps to the desktop and across its digital trunk network. The cost to support the option, however, was seen as excessive because a single wideband port required a dedicated ISDN PRI port circuit card that could cost several thousand dollars. Fujitsu was the first to offer wideband data communications on its F9600 PBX, but customer demand was weak. Other PBX suppliers soon followed the Fujitsu announcement with their own ISDN PRI–based data communications option, but total sales of the option to date have failed to reach 1 percent saturation.

Another PBX system attempt to make a dent in the data communications market came in the mid-1990s when Intecom introduced an Ethernet hub and workstation interface option fully integrated into its port cabinet design. Broadband fiber optic loops between the distributed port cabinets handled intrasystem data traffic and could support Ethernet 10BaseT transmission standards. The broadband data communications option was priced higher than existing LAN interface and switching equipment and failed to find a market.

More than 20 years after the first attempts to position the PBX system as a data communications networking solution, sales of PBX data modules are negligible. The only appreciable data traffic transmitted across a PBX system today is analog-based data communications generated by modems. PBXs are used primarily as a back-up system when LANs are down for service or repair. Ironically, the often unreliable nature of enterprise LANs has made the PBX an invaluable spare data network solution, forcing many voice communications managers to install a significant number of analog ports in support of data modems for use in emergencies. PBX data solutions may not be high speed, but they are reliable.

Basic Voice Call Station/System Features | Feature/Function Enhancements

Do station users really need six variations of call forwarding? Do managers still “buzz” their secretaries? Although PBXs have many call forwarding options and still retain the manual signaling (buzz) feature, the most significant station/system feature enhancements during the past two decades have been to improve incoming call coverage, support the needs of the new mobile workforce, and simplify the administration and maintenance operations of the system manager.

An important PBX feature developed in the days before voice messaging systems invaded the workplace was programmed call coverage. Programmed call coverage was a form of enhanced call forwarding, with some important distinctions. First introduced in 1983 by AT&T on the System 85 PBX, call coverage did not receive the market attention it deserved during the 1980s and 1990s, but renewed interest in personalized call screening and routing to improve communications service levels has revitalized the feature. Call coverage capabilities on current-generation PBX systems allow station users to define where incoming calls are directed when they are unable to answer the call and program the coverage path based on who is calling (CLID, Automatic Number Identification [ANI], internal calling number, call prompt), where the call originated (internal or external to the system), how it arrived into the system (trunk group ID), or when a call is placed (time of day, day of week). Building on the concept of call forwarding, personal call coverage programming redirects calls to a defined path of answering stations and will default to the called party’s voice mailbox only as a last resort. Calls will not be redirected to the forwarding position or voice mailbox of a station user defined in the call coverage path; the originally called party’s coverage path overrides intermediary station user call forwarding commands.

Call coverage tables and station user programming was not possible before the development of digital PBXs. The new CTI-based PBX system designs allows station users to program caller-specific call coverage paths based on identified callers. The personal call coverage function in these new-generation systems is supported at the station user desktop (a PC client softphone), not at the common control call processing system. The objective of personalized call coverage features is to reduce dependency on voice mail systems because a human answering station rather than a noninteractive machine might be preferred by the caller. Voice mailboxes should be the last option in a call coverage environment, not the first or only option.

The new mobile workforce includes station users who are rarely in the office and workers who do not have permanent desk assignments because they are constantly moving or their job function is not desk based. To support these mobile workers, it is necessary to dissociate a station user’s telephone directory number from a physical telephone instrument. Hoteling, a feature designed to support workers who work at different desks throughout the enterprise, allows station users to log into the system from a telephone and reassign their directory number to their chosen telephone. In addition to their telephone number, the individual’s station user profile (service levels, call restriction levels, group assignments) is also assigned to the physical telephone location. Account codes and call records are maintained for the station users for each telephone they use. When done using the telephone, after 1 hour, or 1 week, or 1 month, the station user logs out, freeing the telephone for the next mobile worker. Hoteling is becoming very popular in sales offices. The feature can significantly reduce system costs by optimizing common equipment hardware, telephone instrument, and cabling requirements and, more importantly, minimizing real estate requirements (fewer dedicated desks/telephones, less office space).

Today’s mobile workers who are rarely at a fixed telephone location also benefit from recent feature enhancements. The find-me feature allows station users to program their telephone to direct calls to other telephone numbers outside of the PBX system. More than one external number can be programmed. For example, on a no-answer call at the station user desktop, the call can be forwarded to another telephone number after a selected number of rings; if there is no answer at the external number, another telephone number is dialed, and the call is redirected. External telephone numbers likely to be programmed include cellular telephones, home, conference facility, remote office branch, or even a hotel. A relatively recent teleworker option available on some PBXs allows station users to bridge their line appearance to a telephone external to the system. The concept of the PBX as a mobility server can significantly improve call coverage, reduce lost or abandoned calls, and increase the number of successful call attempts between caller and called parties.

Another category of mobile workers consists of station users who require a telephone away from the formal office environment. Known as teleworkers, these station users require their high-performance telephones to function away from the workplace and receive incoming calls redirected to their remote desktop. The original teleworker option was an off-premises extension (OPX) station using highly tariffed telephone trunk circuits to link remote analog station equipment to the main PBX system. Expensive and low-performance analog OPX stations have evolved into affordable and high-performance digital desktops. The same digital telephone supported behind the PBX at the office can be supported remotely with several options, including distance extender modules and analog trunk carrier facilities, ISDN BRI services and equipment, and the recently available IP workstation (hard telephone or PC client softphone).

The most important system feature enhancements during the past decades have been systems administration and maintenance tools. The early PBX management terminals required high-level programming skills and weeks of training. A typical station move, add, or change operation could require at least 15 minutes of keyboard entries. After booting up the systems management terminal the administrator was met by a blank monitor screen waiting for a programming command. There were no menus, on-screen help command, or point, click, and drag. Computer technology evolved during the 1980s and so did PBX management tools. By 1990 a systems management terminal had a basic graphical user interface (GUI), usually a menu selection list and formatted screens. By 2000 PBX management tools were accessed through a web browser via the Internet, and a sophisticated GUI simplified the administration process. Few keyboard entries are now required, and access to a common metadirectory server simplifies the initial station user directory entry.