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NZQA Expiring unit standard 17493 version 7 Page 1 of 8

The Skills Organisation SSB Code 100401

© New Zealand Qualifications Authority 2015

This unit standard is expiring

Title Demonstrate basic knowledge of telecommunications switching and transmission

Level 3 Credits 20

Purpose This unit standard covers basic underpinning knowledge for people engaged in installation and maintenance of telecommunications switching and transmission systems. People credited with this unit standard are able to demonstrate: – basic knowledge of alternating current and transmission

line theory; – basic knowledge of digital multiplexing and hierarchies; – basic knowledge of digital switching principles; – basic knowledge of telecommunications bearers and

bearer systems; – basic knowledge of telecommunications transmission

installation and testing practices; – basic knowledge of the principles of a broadcast control

system and a coaxial or fibre cable communication system for provision of customer services;

– basic knowledge of data transmission; – basic knowledge of telecommunications alarm

management and monitoring systems; – basic knowledge of common switching and transmission

support services; and – an awareness of emerging telecommunications switching

and transmission technologies.

Classification Telecommunications > Telecommunications - Service Delivery

Available grade Achieved

Explanatory notes 1 This unit standard has been designed for learning and assessment off-job. 2 The term basic knowledge is used to describe the underpinning knowledge required

by trainees to support the range of practical installation and maintenance activities assessed by Unit 17487, Install and maintain basic telecommunications bearer or switch plant and equipment. This knowledge is typically acquired during second and third years of training of a 4 to 5 year training programme.

3 References Electricity Act 1992; Electricity Regulations 1997;





Telecommunications Act 2001; Telecommunications [(Residual Provisions)] Act 1987; and their subsequent amendments and replacements. 4 Definitions ASR – an Alarm Sender and Receiver. BSF – Basic Signalling Frequencies, or Basic Signalling Frames. Cable – any or all of copper cable, fibre optic cable, coaxial cable. DDN – Digital Data Network. DSTN – Digital Services Transmission Network. EFTPOS – Electronic Funds Transfer Point Of Sale. Emerging technology – any technology which is at the development stage, or in early

stages of production and commercial use overseas, but is not yet used commercially in New Zealand.

Industry practice – those practices, which competent practitioners within the industry recognise as current industry best practice.

ISDN – Integrated Services Digital Network. LDC – Leased Direct Circuit. MFC – Multi Frequency Codes. MUX – Multiplexing equipment. PCM – pulse code modulation systems. PDH – Plesiochronous Digital Hierarchy. PMUX – Primary Multiplexing equipment. POTS – Plain Old Telephone Service. PSTN – Public Switched Telephone Network. RNMU – Remote Network Management Unit. SDH – Synchronous Digital Hierarchy. SS7 – Signalling System No.7. VMUX – V-Multiplexing equipment. xDSL – various (x) digital subscriber line systems. 5 Range

a The phrase in accordance with current industry practice is implicit in all evidence requirements in this unit standard.

b The use of mathematics is not required except where calculation is specifically mentioned.

6 The depth of knowledge of the subject matter is such as could typically be learnt

during a six week full-time course.

Outcomes and evidence requirements Outcome 1 Demonstrate basic knowledge of alternating current and transmission line theory. Evidence requirements 1.1 Reactance and impedance are defined, units stated, and calculated.

Range impedance calculations – at any given frequency for simple three-element series and parallel circuits.





1.2 Vectors are used to show phase relationships of voltages and currents in series

and parallel circuits, and to calculate their resultants graphically. 1.3 Resonant frequencies for simple series and parallel circuits are calculated. 1.4 The properties of transmission lines are outlined.

Range reference to – primary constants, definition of transmission loss, variation of loss with frequency, characteristic impedance, reflections, termination, noise, near and far end crosstalk.

1.5 The basic principles of 2-wire and 4-wire transmission are described.

Range resistive, transformer, and electronic hybrids; balance networks; formation and prevention of echoes and instability.

1.6 The properties of fixed and adjustable attenuating networks and equalisers are

described. Outcome 2 Demonstrate basic knowledge of digital multiplexing and hierarchies. Evidence requirements 2.1 The principles of digital multiplexing are outlined from speech to 64Kb/s channel

(time slot) to a single frame.

Range analogue – digital conversion, sampling, time division multiplexing, demultiplexing, digital-analogue conversion.

2.2 The digital hierarchy is developed from lower order to higher order MUX.

Range lower order – DS1 (1.55Mb/s and/or E1 (2Mb/s). 2.3 The principles of different types of digital multiplexing systems are outlined.

Range VMUX, Skip MUX, drop and insert MUX. 2.4 SDH and PDH hierarchies are outlined and compared in terms of what they are,

application, and configurations.

Range outline to include function of drop and insert MUX. 2.5 The concept of diversity is described with reference to self healing rings and

hitless switching. Outcome 3 Demonstrate basic knowledge of digital switching principles.





Evidence requirements 3.1 The operation of a typical local digital exchange is outlined with the aid of a

block diagram indicating all major functions of the switch. 3.2 Network architectures and synchronisation principles are outlined. 3.3 Basic principles and practices of ISDN are outlined. 3.4 Basic principles of signalling systems are outlined.

Range BSF, MFC, SS7. 3.5 The principle of operation of remote line units is outlined. 3.6 Basic practices relating to the installation and maintenance of switching

systems are outlined. Outcome 4 Demonstrate basic knowledge of telecommunications bearers and bearer systems. Evidence requirements 4.1 The characteristics and limitations of copper cable for use in POTS, xDSL, and

PCM systems are outlined.

Range typical impedance, variation of loss with distance and conductor size, maximum effective distance.

4.2 Principles of operation of digital subscriber line systems are outlined.

Range digital subscriber – typically include 2Mb/s line systems interfaces. 4.3 PCM bearer system principles and practices are outlined.

Range nature of line signal, line terminals, power feeding, regenerators, permissible error rates, limitations through crosstalk, regenerator drawings.

4.4 The characteristics of coaxial cables are outlined.

Range typical impedance, variation of loss with distance and conductor size, maximum effective distance.

4.5 Fibre optic cable principles and practice are outlined.

Range construction, principles of operation, low and high power fibres, typical losses and how they are minimised, power measurement, safety precautions, crash test, fibre splitters, fibre reticulation plans.





Outcome 5 Demonstrate basic knowledge of telecommunications transmission installation and testing practices. Evidence requirements 5.1 The principles of earthing for safety and for minimisation of noise and

interference are outlined. 5.2 Installation requirements for location, space, and support mechanisms are

outlined in relation to small and large equipment installations. 5.3 The principles of common transmission measurements are outlined, and units

stated where appropriate.

Range bit error rate (BER), loss v. frequency, psophometric noise, attenuation, crosstalk, time division reflectometry (TDR), optical time division reflectometry (OTDR), clocking and synchronisation jitter and slipping.

5.4 The use of common transmission measuring instruments is outlined or

demonstrated.

Range frequency sweep set, transmission impairment measuring set including measurements of psophometric noise and loss, data line analyser, PCM line test set, bit error rate measuring set, crosstalk measurement, time domain reflectometer.

5.5 The uses of high and low impedance terminations are explained in terms of

effects on the measurement and the network if wrongly used. 5.6 The principles of PCM fault location are outlined.

Range loop back cards, standout jigs. Outcome 6 Demonstrate basic knowledge of the principles of a broadcast control system and a coaxial or fibre cable communication system for provision of customer services. Evidence requirements 6.1 A typical control system of commercial radio programmes is outlined with the

aid of a block diagram, and with reference to major components and their functions.

6.2 A typical coaxial or fibre cable communication system for provision of customer

services is outlined with the aid of a block diagram, and with reference to major components and their functions.





Outcome 7 Demonstrate basic knowledge of data transmission. Evidence requirements 7.1 Basic concepts of data transmission are explained.

Range typical analogue and digital data transmission systems, synchronous and asynchronous data transfer, typical transmission levels and their adjustment, handshaking, simplex, half duplex, full duplex.

7.2 Commonly used data protocols and interfaces are identified and their key

features and applications stated. 7.3 A typical ISDN network is described with reference to purpose, operation, major

hardware components, and typical interfaces. 7.4 A typical digital service transmission network is described with reference to

purpose, operation, major hardware components, and typical interfaces.

Range point-to-point and point-to-multi-point circuits, connection and network management devices.

7.5 The function and operation of a typical network terminal unit (NTU) is explained. 7.6 The simultaneous carrying of various networks on digital transmission systems

is outlined.

Range DDN, POTS, ISDN, Internet, LDCs. 7.7 An EFTPOS terminal is described with reference to operation and functional

components. 7.8 A typical telemetry system is described with reference to operation and

functional components. Outcome 8 Demonstrate basic knowledge of telecommunications alarm management and monitoring systems. Evidence requirements 8.1 A typical alarm management and monitoring system currently available in New

Zealand is outlined.

Range outline to include reference to – facilities provided, network structures, network administration, components, network centre, customer equipment.





8.2 Alarm collection devices are described with reference to principles of operation.

Range devices may include but are not limited to – ASRs, interface management and collection units, for example, RNMU, exchange test access devices.

8.3 An outline of maintenance practices is given, with particular mention of work

clearances. Outcome 9 Demonstrate basic knowledge of common switching and transmission support services. Evidence requirements 9.1 Typical power supply systems are outlined with reference to battery backup and

emergency generator. 9.2 The operation of security access and fire protection systems are outlined with

reference to purpose and function.

Range fire protection – gas suppression, sprinklers, smoke alarms. 9.3 The purpose and function of air-conditioning systems is outlined in relation to

equipment rooms. Outcome 10 Demonstrate an awareness of emerging telecommunications switching and transmission technologies. Evidence requirements 10.1 Emerging technologies are briefly described with reference to purpose, facilities

offered, and how the technology will integrate with existing switching and transmission systems.

Range any two emerging technologies which are currently of interest to

the industry.

This unit standard is expiring. Assessment against the standard must take place by the last date for assessment set out below.





Status information and last date for assessment for superseded versions

Process Version Date Last Date for Assessment

Registration 1 30 May 2000 31 December 2016

Revision 2 3 April 2001 31 December 2016

Revision 3 13 November 2002 31 December 2016

Rollover and Revision

4 20 April 2006 31 December 2016

Review 5 18 July 2013 31 December 2016

Rollover 6 17 April 2014 31 December 2016

Rollover 7 16 April 2015 31 December 2018

Consent and Moderation Requirements (CMR) reference 0003

This CMR can be accessed at http://www.nzqa.govt.nz/framework/search/index.do. Please note Providers must be granted consent to assess against standards (accredited) by NZQA, before they can report credits from assessment against unit standards or deliver courses of study leading to that assessment. Industry Training Organisations must be granted consent to assess against standards by NZQA before they can register credits from assessment against unit standards. Providers and Industry Training Organisations, which have been granted consent and which are assessing against unit standards must engage with the moderation system that applies to those standards. Requirements for consent to assess and an outline of the moderation system that applies to this standard are outlined in the Consent and Moderation Requirements (CMR). The CMR also includes useful information about special requirements for organisations wishing to develop education and training programmes, such as minimum qualifications for tutors and assessors, and special resource requirements.