Click here for Norstar Modular 32

BT Meridian Norstar Modular is a key telephone system with a maximum capacity of 128 ports. The Central Control Unit provides capacity for 8 Exchange Lines and 24 Extensions, the system can be expanded by the addition of Extension and Line Modules. Each Extension Module provides for an additional 16 extensions. Each Line Module provides for an additional 12 Exchange lines via Line Cartridges (3 Cartridges, four exchange lines per cartridge). Up to 6 modules can be added to the system in any combination. The CCU, box connection and all modules are wall mounted.

Four types of digital extension telephones (7100, 7208, 7310 and 7324) are available in three colours (Black, Dolphin Grey and Beige). A busy lamp field is available for connection to the 7310 telephone. A Central Answering Position is available for connection to the 7324 telephone.  Headset working is available on the 7208, 7310 and 7324 telephones.

Click here for 7000 series telephones

A wall mounted Analogue Terminal Adaptor (ATA) is available to allow the connection of two wire analogue telephones, answering/ facsimile machines etc. A Station Auxiliary Power Supply (SAPS) is available which increases the normal extension line length.

A wall mounted AC15 adapter is available to allow the provision of AC15A private circuit signalling, a maximum number of 14 x AC15 adapters can be provided per system, the Modular system can be used as a networking switch.

A wall mounted Call Logging Interface (CLI) will be available which provides V24 output to a printer or suitable call management system. This interface will not be available at launch. (Norstar does not support SPM).

The AC15 and CLI adapters are connected to extension ports , the provision of either of these adapters reduces the capacity of the system by one extension.

Made by Northern Telecom, now called Nortel.

Supplied in the UK by BT.

Approved for direct connection to the PSTN using loop disconnect or MF signalling or by working as a (List A) subsidiary system (loop disconnect or MF signalling) connected to a (List C) PBX or as a Host system (List C).

The following two restrictions have been imposed by BABT. They have been imposed because the system failed to meet the test specification on Longitudinal noise. NT are working to correct the problem and hope to resolve them by February 1992.

If the Modular system is connected as an off premises subsidiary system to a host switch via public network cabling (BT or Mercury) connection is restricted to the 8 exchange line ports of the 8+24 Control Unit only.

On-premises connection or connection by a privately provided link are not restricted.

Connection of either of these types of circuit is not permitted if that connection is via public network cabling (BT or Mercury).

On premises connection or connection via a privately provided link are not restricted.

Software level 4.0 is approved for use with Norstar Modular, this software is provided on a cartridge which plugs into the CCU. The cartridge must not be removed/replaced with the system powered up.

Exchange lines can be either earth calling, guarded clearing: loop calling, unguarded clearing or loop calling guarded clearing. The type of signalling is determined by programming within CONFIG.

A Functional Earth is provided when earth recall is required on the system or when earth calling exchange lines are required.

Although extensions only require single pair cabling, multi-pair cabling may be used.

The single pair terminates on terminals 3 and 4 of a secondary Line Jack Unit (LJU).

The approval requirement for Norstar is that one power fail (master) LJU must be provided for each five exchange lines on the system. The installation cost of the system includes the provision of power fail LJU's (not the telephones) within 3 metres of the Box Connection.

Future maintenance requirements must be considered when planning system location and cabling.

A Station Auxiliary Power Supply (SAPS) can be fitted to the extension L.J.U. which increases the extension line length from 300 to 790 metres.

Testing has shown Norstar systems to have very good immunity to mains interference. External filters (e.g. Protector Mains 2A & 4B, ONEAC) need not be fitted as standard.

Music on Hold and External Paging connections in the box connection should be cabled to a Block Terminal 80A sited within 3 metres of the box connection.

BT customers reported Norstar faults to the Meridian Norstar Adviceline. The reported fault will be analysed to determine whether it is a genuine fault or due to customer misunderstanding of the Norstar system. Genuine faults will then be forwarded by the Adviceline to the nominated Norstar fault reception point within the Zone concerned for attention.
Faults within the Norstar system are located by unit/terminal change out procedures documented in the Troubleshooting and Maintenance Session sections of the Installation and Maintenance Guide.

The customers data is stored within the Data Cartridge 30A, this memory is battery backed. If the CCU and/or the Software Cartridge 30A have to be changed the existing Data Cartridge should be retained and plugged into the new item(s), this prevents the need to reprogram the customers data.

If programming data has been lost due to a fault condition, the maintenance engineer should perform the STARTUP and CONFIG programming only, the customer is to perform the ADMIN programming.

BT receive an 18 month warranty from Northern Telecom from the date of manufacture.

The date of manufacture can be determined by the last four digits of the ten digit serial number in the form YYWW.
The warranty expiry date can be determined by the first four digits of the six digit number on the left of the label in the form YYMM00.

                   Release Number                BT Item Code

                         01             NORSTAR   I/C 376317
          NT Code - -  NT7B01           TELE M7310 BEIGE - - BT Title
                       911200                      049020

Warranty Expiry Date(YYMMOO)     Factory Code(O4) Date of manufacture(YYWW)

e.g. The above item has a date of manufacture of the 20th Week 1990, and a warranty expiry date of the end of the 12th month of 1991.

Normal capacitance 'A' wire to 'B' wire (8.5K ohm + 1.8pF in series), Earth calling or loop seizure.


Not all telephones are suitable for use as power fail emergency telephones on installations with earth calling exchange lines. This is because earth recall is required to get dial tone on this type of exchange line. Almost all telephones have this capability, the more modern telephones use a transistor to apply the earth. The circuit to power the transistor is designed assuming that the exchange earth and battery connections exist, which is not the case with earth calling lines.

The following telephones are suitable:-
Viscount, Tribune, Venue, Prelude, Prelude+, Vanguard 10 (only)

The following telephones are NOT suitable:-
React (the whole range), Vanguard, Tandem.

Taken from BT information

No expansion 1 expansion cab 2 expansion cabs

Technical Specifications:
Max Capacity: 128 ports + 80 exchange lines, 24 extensions + 8 exchange lines, 120 extensions
Switching: Fully digital, non-blocking
Control: Stored program on up-gradable cassette
Private Circuit Cap: 14
Recall: Timed break or earth
Power Requirements: 240V AC/50Hz
Power Consumption: 24W(basic system), 120W(fully loaded)
Operating Temp. Range: o(inf)-50WC
Humidity Range: 5%-95%

Width Height Depth
CCU 395mm 625mm 171mm
Box Connection 210mm 790mm 95mm
Line Module 198mm 625mm 171mm
Extension Module 98mm 625mm 171mm

Central Control Unit: 9.0 kg
Box Connection: 3.9 kg
Line Module: 6.0 kg
Extension Module: 2.4 kg

Additional Information (North American)

NORSTAR Modular 8 x 24
The basic 8 x 24 KSU expands easily by simple self contained add-on trunk and station modules.

Any combination of six modules can be added to the KSU to a combined maximum of 128 total ports.

An expansion card is required to add modules to the 8 x 24 KSU. Expansion cards come in either 2 module expansion or 6 module expansion. This expansion card plugs directly into the KSU. The trunk and station modules then connect to the expansion card with a single plug in cable.

Station Module 0 x16 provides for the addition of 16 station ports. The Trunk module 12 x 0 provides for a maximum of 12 trunk ports. The trunk module by itself does not provide trunk access. Trunk cards 4 x 0 go into the trunk module (maximum 3 trunk cards) per trunk module.

NORSTAR Compact ICS 4 x 8
The Norstar Plus Compact ICS is packed with well over 100 powerful features, like integrated automated attendant, which easily answers your calls and routs them to the right person or group.
The Compact ICS is initially configured 4 lines by 8 stations. It is expandable to 8 lines by 24 stations, with a software and hardware upgrade.

NORSTAR Modular ICS 0 x 32 (North American)
The Modular Integrated Communication System (ICS) provides the most power and speed ever available in a business communication system. Its ingenious combination of hardware and software puts this new system in a class by itself . The Modular ICS is designed from the "ground up" to take full advantage of the very latest advances in digital technology and communications. This next generation Norstar brings the power and flexibility of much larger systems within the reach of companies with smaller port and traffic requirements.
The Norstar Plus Modular ICS represents the smartest investment you can make to help successful companies like yours thrive today, tomorrow, and for years to come.
The Norstar ICS is T1 ready and expandable to over 250 total ports. It is expandable in the same way that the 8 x 24 is (see above). The basic KSU is 0 lines by 32 stations. The 0 lines in the KSU allows for the open architecture ability to add 4 x 0 trunk cards or 24 channel T1 cards (maximum of 2 T1).


The Modular 32 is the most recent version of the Modular system. It is pre-configured for 0 lines and 32 extensions and can be upgraded to a maximum 188 ports by the addition of trunk and extension modules. The system provides ISDN30 access and later software releases provide additional features: the I420 software release allows the installation of 8cct BRI cards directly into the CCU (Trunk slot) or Global Trunk Module. The Modular Plus is as the I420 software release, but the programming sequences have been modified to physically appear more like the new Compact Plus programming. Additional analogue trunks and extensions are added in modules in the same way as the original modular.

Extract from BT CSI No. 370 (1996)

Disconnect from mains supply before connecting any units. Additional Modules are connected to the CCU via fibre optic cables to transmit (low power) ‘group 1 classification’ optical signals. Under normal ‘group 1 classification’ safety precautions there is no need to power down the system whilst connecting fibre optic cables but do not look directly into the fibre optics at close range whilst units are powered up.

The Norstar Modular 32 CCU is similar in appearance to and supersedes the existing Modular 8+24 CCU for new Norstar Modular installations only. Norstar Modular 8+24 will continue to be maintained on a like for like basis.

Modular 32 is compatible with the existing range of Norstar terminals and most add-on units used on Norstar Modular 8+24 (see ADDITIONAL INFORMATION) and incorporates the following differences and enhancements to the Modular 8+24

  1. (a) System software is developed from Phase 3 (ENET) Software and is stored on a single plug in Software Feature Cartridge (not interchangeable with existing Modular) - Customer data is stored within the CCS as with Norstar Compact. The current software shipped on new systems and available for upgrades, is 3.04. (DASS Enhancements). This allows the Modular 32 to provide both Startalk and Mobility (Cordless Handset working). An additional feature, ‘DDI Busy’ has also been added. Upgrades to existing, pre DASS Enhancements, systems are also available. See CFN Voice - Meridian Norstar No 037 for further details of DASS Enhancements. See CFN Voice - Meridian Norstar No 038 for details of software release levels for Modular 32.
  2. System software also incorporates cordless handset working (Norstar 32 Companion) which is activated by entering a ‘Keyword’.
  3. As supplied the CCU is equipped for 0 exchange lines and 32 extensions. It incorporates two slots for addition of ‘Line interface Cartridges’ on installation, these may be ‘30 channel (ISDN3O)’ Cartridges or ‘4 Line Analogue’ Cartridges (or one of each). The second slot can be left blanked off if only one line Interface Cartridge is required.
  4. The CCU has a slot for a new ‘Slimline’ 2 or 6 port expansion Cartridge for connecting existing (Analogue) Line or Extension Modules to increase capacity (the new slimline Cartridges can also be used in Modular 8+24).
  5. Separate Power Unit - field replaceable plug in unit.
  6. CCU casing is 300mm wide (slimmer than Modular 8+24 CCU but same depth and height) and incorporates an integral cable trough with end cap. The CCU cover is held shut by a fixing screw.
  7. New ‘Barriered Line Cartridge’ is slimmer than existing version and can be used on existing Modular CCUs and Line Modules. (Existing Line Cartridge can still be used in Line Modules as previously).
  8. Revised Box Connexion layout.
    On ISDN 30 installations, this will come with ready terminated Coaxial cables for connexion to ISDN 30 Digital Network.
  9. Capacities (with expansion modules) are
    Analogue Lines - up to 80+32 or 8+128
    Digital Lines - up to 60+128 or
    Digital + Analogue - up to 34+128 or 132+32
  10. Access to certain ISDN 30 Supplementary Services:- Direct Dial In (DDI), Calling Line Identification (displayed on Norstar Terminal), Call Charge Information (displayed on Norstar Terminal), Fast ‘last number redial on External calls’.

Note: Modular 32 is NOT yet available for other ISDN services:- Customer Controlled Call Diversion on ISDN 30 lines,
1.420 extensions for Group 4 Fax or Video conferencing etc.

Northern Telecom (Trading in UK as NorTel).


Approved for direct or indirect connection to the Analogue or Digital Network under Approval Number NS/1250/23/M/602494 and covered by BABT/PXML/PBX.0148 issue 8 onwards.

A dedicated 13 Amp type Mains Socket outlet is required for the CCU.
The Box Connexion 30B comes with Co-axial cables approx 4 Metres long to plug into the ISDN 30 terminating unit. These may be extended if necessary by ISDN 30 provision Groups or Companion trained engineers using crimp fit co-ax connectors on 75 ohm co-ax cables.

For Norstar 32 connected to analogue lines, similar practices as for existing Norstar 8+24 apply.

The ISDN 30 service will be provided via co-axial cables (one pair of cables per ISDN 30 interface Cartridge). These are plug ended (with BNC connectors) for connection to the ISDN 30 service terminating unit. ISDN 30 provision groups normally put contact information on CSS.

Norstar Installers will need to liase with the local ISDN 30 Provision group in advance to arrange commissioning as this may require an engineer in attendance at the Exchange (especially where the Norstar 32 is replacing an existing switch and the customer is transferring existing analogue telephone numbers onto the Norstar 32).

Where the customer has requested Direct Dialling In (DDI) service, the Norstar will need to be programmed to receive the correct number of digits forwarded by the exchange.

A Keyword process is used to open up the software for cordless handset operation, this requires the installer to dial up a database at NorTel and enter the Norstar System Identity number, the NorTel order number, Feature Number
and Facility Code as shown on the shipping papers supplied with the kit. If these numbers are correctly entered and identified by the database, a code number will be returned which must be programmed into the Norstar to open up the facility.

A similar Keyword process is also used to open up additional ISDN trunks where the customer has requested more than the default value of 5 trunks.

Where additional trunks are to be opened up on an installed system, the order information for the keyword will be sent to site in an envelope marked for the attention of the BT Engineer.

The keyword process is dependent on the Norstar ‘System Identity Number’ which will change if the CCU is subjected to a ‘Cold Start’ or maintenance exchanged, in such cases, contact the Norstar Adviceline for assistance with the keyword process to restore ISDN trunks/cordless handset operation.

Up to 30 Minutes extra time has been allowed for familiarising customers with the additional facilities offered by ISDN 30.

Upgrades - All new Modular 32 systems are shipped with DASS Enhancements software fitted. This allows the Modular 32 to provide both Startalk and Mobility (Cordless Handset working). An additional feature, ‘DDI Busy’ has also been added. Upgrades to existing, pre DASS Enhancements, systems are also available.

Analogue Lines - Earth Calling lines preferred when connected to Analogue exchange lines.
Digital Lines - ISDN 30 loop back testing.

Power Fail Operation
Analogue line Cartridges have power fail relays on the second line of each Cartridge (i.e. on a system with 2 analogue Line Cartridges, Line 2 and Line 6 will be switched through on power fail). This may result in Ring Tone No Reply complaints on the first line of PBX groups during power failure.

Power Fail on Earth Calling Lines
Where the Exchange Lines are set for ‘Earth Calling’ then Power fail Line Jacks must be provided with a recall Earth and the telephones must be capable of Earth Calling. Not all telephones are suitable because the ‘Earth Recall’ button is used to get dial tone on this type of exchange line, most telephones have Earth Recall facility but the more modern telephones use a transistorised circuit to apply the earth. The circuit to power the transistor is designed assuming that the exchange earth and battery connections exist on the A & B wires, which is not the case with earth calling lines.

The following currently available ST supplied telephones are suitable for Earth Calling:-
Converse 100, 180, 250.

Major Equipment Failure (MEF) or Power Failure - When a Modular 32 with ISDN 30 experiences an MEF or Power Failure, the exchange will automatically return Busy Tone to incoming callers. As stated in Quality Assessment Guide 2 (QAG2), one outgoing PSTN line must be provided at the PBX location for emergency use. This need not be provided on the PBX, but if it is then an approved reserve power supply may be required to support the outgoing service.

Where customers require service during mains failure as a chargeable extra, this can be achieved by:-
Standby power for the Norstar 32 (and if necessary, for the ISDN equipment also, depending on the method of ISDN 30 provision). Having analogue lines in addition to ISDN 30.
Applying for ISDN 30 lines to be automatically diverted at the Exchange in the event of ISDN 30 service failure (the lines can be diverted a different address or even to analogue lines on the Norstar).

Compatibilities - With the launch of DASS Enhancements software, new supplies of Modular 32 will now support StarTalk with Cordless handset working.
Existing, pre DASS Enhancements, systems may be upgraded. See INSTALLATION/COMMISSIONING - Upgrades for details.

AC15A with Cordless handset working - (incompatible)

The launch version StarTalk Mkl unit is not compatible with Modular 32, this has been superseded by StarTalk Mk2 (which is fully backwards compatible on Modular 8+24).

Call Logger Interfaces (CLI):
Modular 32 + Existing CLI + CM6000 (or 3rd party supplied logger) with existing software. Analogue lines & ISDN 30 -  Standard format only supported, AC15 or target lines will not be recorded.

Modular 32 + (New) CLI lB + CM6000 (or 3rd party supplied logger) with new software: Analogue lines - Standard Format only. ISDN 30 - Standard format, AC15 and Target lines will be recorded.

CLI lB on Modular 32 will only support CM6000 (or 3rd Party supplied) loggers which have been upgraded with Modular 32 compatible software. CLI lB includes certain bug fixes and can replace Existing CLI on existing Compact or Modular 8÷24 installations with CM6000 (current or new software).


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Last revised: November 23, 2021