The following
is a slightly modified extract of my Training Report submitted to the Faculty
of Engineering after a 3 month training stint at Metropolitan Communications
Ltd. All views expressed are exclusively mine.
The BP250 and BP50 phone systems
The BP250 and BP50 phone system is a modern state of the art PABX system provided by Ericsson. It utilizes the same technology as the BCS 150 which it supersedes. During the training period the BP250 was encountered at many customer sites and I gained experience in both hardware and software maintenance of the BP250 system. The BP50 is a smaller version of the BP250 system.
General Description
The BP250 is a wall mounted system consisting of 1 to 3 cabinets. It can handle a maximum of 56 trunk lines and 192 extensions in an office environment or 288 extensions in an hotel environment. The system is connected to the public exchange through digital or analogue trunk lines. The system takes a maximum of 60 simultaneous calls. A practical limit is 56 calls.
System Features
The BP250 is an extremely flexible and configurable system which provides a vast number of features and facilities to optimize efficiency of communication for users.
System configuration
The system is configurable in many ways. Some possible and common configurations are given below and clarified in figure 3.01.(Well if you want to see it it's in my report but I'll go through the trouble of scanning and posting it only if someone requires it)
A PBX Operator controlled system
A key system
An executive secretary system
A subsystem to centrex or other PBX systems
An ACD system
An hotel system
A tenant (multi PBX) system
These configurations are not mutually exclusive and a system can possess all or some of the above simultaneously. The more common ones I encountered are discussed below.
A PBX Operator Controlled System
This is by far the most common business approach of utilizing the BP250 system. All incoming calls are presented to the operator in one common queue. System allows employment of a PC operator or blind operator.
The trunks are presented on keys on system telephones. An incoming call is presented on all telephones in which the relevant trunk is represented.
An Executive Secretary System
An optional number of executives and secretaries can be set. Calls can be diverted, toned busy, and returned on no reply. A dedicated inter secretary-executive link is
Several mutually independent organizations share one system. A maximum of 8 companies is allowed. Each company can have its own private trunk lines. I did not see any such application on the field during my training.
Automatic Call distribution
Calls are evenly distributed between clients on a first in first out FIFO basis. However priority can be set. A maximum of 40 call receiving agents and 48 incoming trunk lines is serviceable.
ACD Management System Personal Computer Software
This offers real time monitoring of agents, calls and service level. Software offers very detailed reports on individual agents or overall performance statistics which can be extremely useful in a service industry for information and planning services.
Hotels require an additional range of features and are probably the most demanding of PBX users. A host of features is included in BP250 for use as hotel phones. These include:
- Special guest room phones
- Wake up Calls
- Check in / Check out
- Do not disturb
- Call forwarding
- Specified accounting/ direct accounting
- Checkout bill printout
- Room status report
- Message waiting light
- Message waiting list
- Read, alter room status
This is probably the phone system of the future but it has not made an entry into the Sri Lankan market yet.
I had an opportunity to see many types of uses at various customer sites. I was most fortunate to visit several times the system employed at The Emirates Airlines office situated next to MCL. The system was being used as a multi-configured system. Its features included
A PBX Operator controlled system
An executive secretary system
An ACD system with ACD Management system
I also got exposure to BP250 and other hotel systems in Sri Lanka.
Printed Board Assemblies (PBAs)
As mentioned earlier most facilities are introduced to the system through separate PBAs. These are referred to as 'boards' or even more affectionately as just 'cards'.
The BP50, being a smaller version of the BP250 can accommodate 9 boards in one cabinet. It has a built in power supply and MDF. This system cannot be expanded to more than one cabinet. The cards used, however, are compatible with the BP250 cards.
The BP250 consists of 1 to 3 cabinets with each cabinet being able to hold 9 boards. The first position in the first cabinet is reserved for the CPU card but the other positions can be used for any card. These cards are interconnected through the back plane via the back plane bus. Versions with a built in transformer or battery charger for battery backup packs are available. The system can be fed by an external source with 36 VAC or 48 VDC. DC-DC conversions are carried out locally in the back plane of the cabinet.
This card holds the central processor in the system and is essential for any system. It is always mounted in the first slot in the first cabinet. It has 1MB (variable) program and data memory, a conference unit, an internal clock, V.24 ports for local operation (maintenance) and printer setup, a modem for remote maintenance, a temperature sensor for protection and an audio port for music input to the system via an outside source like a radio or cassette player.
The newest is the CPU-D4 which is supposedly much better, though practical experience suggests otherwise.
Digital extension card which handles upto 16 digital extensions including the operator console.
Analogue extension card which handles upto 16 standard DTMF analogue extensions.
Bothway trunk unit cards that handle digital trunks or ISDN to the public exchange and a maximum of 30 channels. Analogue DTMF trunks require the REG (register) board instead of the BTU-D card. One popular use is for E1 CAS links. By changing the PROM sets you can use the same card for ISDN PRA (or PRI) links.
Can be used instead of REG boards. These handle maximum 8 analogue trunks 1-4 of which can be through connected to extensions for use during power failure.
Bothway trunk units handling tie lines.
Daughter boards mounted on BTU cards and used for call metering.
Auxiliary cards which provide additional ports for peripherals such as PC operator.
Voice memory unit. Provides about 8 minutes of recorded speech and can 'talk' to 16 parallel lines.
This card has now given way to the VMU-HD card which features, among other things, customizable Auto-attendants and primitive voice-mail functions. Password protected Direct Inward System Access (DISA) is also available through this card.
The BP250 is programmed by a clipper based (?) software called RASC (Remote Access Setup and Configuration), which is not available in the market. If you need or have any hints on RASC programming (which is an art in itself due to its peculiar to say the least- design) you are welcome to contact me.