Office PBX , Office PBX ( PBX ), mini-PBX ( eng. PABX - Private Private Utility Change X ) - an automatic telephone exchange designed for use within the organization. From the PBXs used by the telecom operator , it is primarily distinguished by its focus on a small number of serviced numbers (usually no more than one hundred or two hundred), the separation of the telephone network into "internal" and "external". Depending on the type, it can receive a digital stream from telephone operators, analog lines or through switched networks ( IP-telephony ). Subscriber devices are typically analog phones, digital or IP phones. Using the PBX allows you to refuse to connect each subscriber device (telephone, modem, fax) of the organization to the public telephone network , which would lead to the allocation of a separate line (usually paid monthly) to each subscriber device, and all “internal” calls would go through the PBX telecom operator.
PBX equipment is usually installed in the organization’s premises and commutes calls between extension lines . Additionally, for external incoming and outgoing calls, a limited number of trunk lines (trunks) to the public telephone network are usually available. Organizations across multiple buildings can use trunks (CO, from Central Office) to connect their own PBXs. Trunk lines are typically analog or digital ( E1 , BRI ). The latter, unlike analog ones, are able to process more than one connection and receive calls to several city numbers - DID .
Sometimes the PBX is abbreviated as the English abbreviation PBX (abbreviation for Private Private Change or Change), and PABX (Private Private Change e Change).
The main difference between a production PBX and a public telephone exchange ( GTS ) are:
- the ability to provide fully accessible traffic switching schemes (communication without blocking);
- Intelligent call distribution systems for subscribers or operators;
- the enormous volume of subscriber services provided (for example, Avaya PBXs provide over 800 telephone services);
- support for embedded CRM subsystems and advanced SDK systems for embedding telephone subscription services in automated systems;
- ensuring the provision of subscriber service packages regardless of the location of the subscriber and the method of connecting to the telephone network (mobility);
- high reliability and flexible backup system, providing 100% continuity of telephone communications.
The PBX allows you to save organization costs and reduce communication costs, because when using the PBX, internal calls within the organization are free, the connection time is extremely short, since three-digit numbering is usually used, and each organization can program its PBX to fit its needs, distributing among employees the right to enter the city, the organization’s city lines, setting up voice menus, etc.
On the basis of the PBX, large corporate telephone networks are being built for state and financial institutions, transport management systems, medical institutions, etc. Office PBX programming is carried out using a system telephone or using a special program connected via a port (interface): RS-232 ; USB 10BASE-T . It is usually possible to set a password to enter the programming mode so that unauthorized persons cannot change the specified algorithm of the PBX operation. Such a system telephone should be installed with the secretary or with the secretary and director, however, if the PBX has a sufficient number of expansion cards that support system telephones, these devices can be installed for everyone.
The capabilities of the PBX are determined by its configuration. For example, you can equip a station to the maximum with analogue cards in order to achieve maximum capacity, or you can give priority to city line cards. In addition to these types of cards, there are many other cards, for example, an auto attendant card, a voice mail card, a modem card, a card for connecting a music source, and so on. Different PBX manufacturers may have very different station configurations.
Content
Key Features
- Switching subscribers within the office telephone network.
- The ability of subscribers to make calls to the city (usually with the extension before the city number “9”), that is, the organization of interfacing with the public switched telephone network ( PSTN ).
- Reception of city calls and their direction to the specified internal numbers (see also DISA )
Types of office and office exchanges
Traditionally, telephone exchanges are divided by type of switching and by the number of connected telephone lines (capacity).
By the type of switching, analog, hybrid and digital exchanges are distinguished. Currently, all three types of stations are produced by various manufacturers. Analogue stations are the least cost port. Hybrid exchanges differ from digital in the way of switching the signal. In digital exchanges, the voice signal of the tonal frequency is converted into a coded digital electrical signal (having only two logical values: “0” and “1”). These signals are then switched. In hybrid exchanges, “not digitized,” that is, an analogue electrical signal of a tonal frequency without conversion, is switched. At the same time, the management programs of hybrid automatic telephone exchanges are similar to those used in digital automatic telephone exchanges. The user interface may coincide, and the subscriber of the station in some cases will not even feel the difference between a hybrid and a digital telephone exchange. The term “hybrid lines” means that both system and analog phones can be connected to such lines.
With the spread of the IP-telephony standard, IP-PBXs became widespread.
By Manufacturers
- Alcatel ,
- Avaya
- EADS ,
- Ericsson
- Nortel
- Panasonic
- Samsung
- Siemens
- Tadiran ,
- and etc.
Additional features
- Carrying out reservation of telephone communication from several operators (when communication with one operator is lost, the lines of another are used).
- Call forwarding based on busy line signal, unanswered or unconditional, depending on the time of day and other conditions, that is, scripting calls or dialplans.
- Transfer a received call to another subscriber.
- Off-hook for another party (call pickup).
- Conference call .
- Priority Calls.
- Incoming dialing ( DISA ).
- Interactive voice menus.
- Group call.
- Serial search - the choice of a free trunk for outgoing connections.
- Automatic change of the guidance table depending on the time, day of the week.
- Notification of the subscriber about the off-hook (loud signal to the handset some time after hang up).
- Handsfree, reception and broadcasting of civil defense and emergency signal.
- Management of intercoms.
- Auto redial.
- Differentiation of user rights for city, intercity, international calls.
- Keeping statistics of calls.
- Record and play telephone conversations .
- Automatic switching of city lines to preset numbers by power failure.
- Detailing phone calls by duration and direction.
- Invasion of conversation.
- Speed dial.
- Automatic translation of the operating mode in accordance with the time plan (for example: night hours, weekends, lunch, etc.)
- Hang up of a caller from outside with a subsequent call to this number and connecting it to an internal subscriber or transfer to DISA (a call is made at the expense of the organization).
- Recognizing the direction of an outgoing call (for example: mobile, long-distance, international) and the choice of the necessary operator / line depending on this.
Sources
- Article "What should be a PBX" , author: Ph.D. S.V. Mukhin. Published: issue 5 of the journal Networks and Communication Systems , 2004
See also
- IP-PBX
- Centrex
- Fixed Mobile Convergence
- Virtual telephone exchange
- Asterisk (software implementation of PBX)
- D Optional Service ID ( VAS )
- MTT