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Communications technology

Electronic communication is ubiquitous in homes, offices and urban environments. You probably regularly use mobile devices, Wi-Fi and broadband. What makes such forms of communication possible? How do they relate to each other? Why is their performance so variable? This module gives you an insight into these and other questions by looking at the fundamental principles of communications technologies. Through these principles, you’ll gain an insight into the possibilities and constraints of modern communications technology.

Modules count towards OU qualifications

OU qualifications are modular in structure; the credits from this undergraduate module could count towards a certificate of higher education, diploma of higher education, foundation degree or honours degree.

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Module

Module code

TM355

Credits

Credits

  • Credits measure the student workload required for the successful completion of a module or qualification.
  • One credit represents about 10 hours of study over the duration of the course.
  • You are awarded credits after you have successfully completed a module.
  • For example, if you study a 60-credit module and successfully pass it, you will be awarded 60 credits.
30

Study level

Across the UK, there are two parallel frameworks for higher education qualifications, the Framework for Higher Education Qualifications in England, Northern Ireland and Wales (FHEQ) and the Scottish Credit and Qualifications Framework (SCQF). These define a hierarchy of levels and describe the achievement expected at each level. The information provided shows how OU module levels correspond to these frameworks.
Level of Study
OU SCQF FHEQ
3 10 6

Study method

Distance Learning

Module cost

See Module registration

Entry requirements

See Entry requirements

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Module details Entry requirements Module registration Study materials

What you will study

Block 1
Block 1 concerns the physical aspects of signals and their environment. You will study the theory and practice of signals (such as how electrical and radio signals can represent data), the propagation of signals through space and through materials, and the physical media that are used to convey signals, such as optical fibres, free space and conducting materials. Issues of noise and spectrum availability are ever-present because they set limits on what is possible. Accordingly you will study and use Shannon’s theorem, which specifies the maximum rate at which information can be sent over a channel of a specified bandwidth in the presence of noise. You will also study some concepts from Fourier’s theorem, which shows how an information-bearing signal occupies a band of frequencies rather than a single frequency.

Block 2
The second block concerns the nature and types of codes that are used to represent digital data. Although digital data is thought of as a succession of zeros and ones, the way those zeros and ones represent data needs ingenuity because perfect transmission in the presence of electrical noise (or interference) is impossible; and noise is unavoidable. In practice, the probability of error must be made sufficiently low, and this is achieved by use of error detecting and error correcting codes, which add extra zeros and ones to the data. You will study some of the main coding methods used to add resilience to signals. You will also look at some of the techniques used to reduce the amount of data imperceptibly so that files can be compressed.

Block 3
The final block looks at the principal types of access network in use. These are the networks used to connect users to the main data and telephony trunk routes. They include mobile data (3G, 4G and 5G), DSL broadband (which is the type delivered over a user’s fixed-line telephone connection), Wi-Fi, optical fibre and co-axial cable. The basic principles of these are covered with a view to uncovering their similarities (such as the increasing adoption of orthogonal frequency division techniques) and the factors that affect the performance of these types of network. The block concludes by looking at the implementation of security and virtual private networks in the context of teleworking.

If you are considering progressing to The computing and IT project (TM470), this is one of the OU level 3 modules on which you could base your project topic. Normally, you should have completed one of these OU level 3 modules (or be currently studying one) before registering for the project module.

Teaching and assessment

Support from your tutor

Throughout your module studies, you’ll get help and support from your assigned module tutor. They’ll help you by:

  • Marking your assignments (TMAs) and providing detailed feedback for you to improve.
  • Guiding you to additional learning resources.
  • Providing individual guidance, whether that’s for general study skills or specific module content.
  • Facilitating online discussions between your fellow students, in the dedicated module and tutor group forums.

Module tutors also run online tutorials throughout the module. Where possible, recordings of online tutorials will be made available to students. While these tutorials won’t be compulsory for you to complete the module, you’re strongly encouraged to take part.

Assessment

The assessment details for this module can be found in the facts box.

Future availability

Communications technology (TM355) starts once a year – in October.

This page describes the module that will start in October 2025.

We expect it to start for the last time in October 2030.

Regulations

As a student of The Open University, you should be aware of the content of the academic regulations which are available on our Student Policies and Regulations website.

Course work includes:

3 Tutor-marked assignments (TMAs)
Examination


Entry requirements

You must have passed one of the following modules:

You should understand the distinction between analogue and digital, and be familiar with:

  • the use of binary numbers to represent digital data
  • sines and cosines.

You should also understand and be able to perform basic manipulation of algebraic terms and to read graphs with linear and logarithmic scales.

To prepare for this module, we recommend Communication and information technologies (TM255) as suitable preparation.

If you have any doubt about the suitability of this module, speak to an adviser.

Register

Start End England fee Register
04 Oct 2025 Jun 2026 £1946.00

Registration closes 11/09/25 (places subject to availability)

Register
This module is expected to start for the last time in October 2030.

Additional Costs

Study costs

There may be extra costs on top of the tuition fee, such as set books, a computer and internet access.

If your income is not more than £25,000 or you receive a qualifying benefit, you might be eligible for help with some of these costs after your module has started.

Ways to pay for this module

Open University Student Budget Account

The Open University Student Budget Accounts Ltd (OUSBA) offers a convenient 'pay as you go' option to pay your OU fees, which is a secure, quick and easy way to pay. Please note that The Open University works exclusively with OUSBA and is not able to offer you credit facilities from any other provider. All credit is subject to status and proof that you can afford the repayments.

You pay the OU through OUSBA in one of the following ways:

  • Register now, pay later – OUSBA pays your module fee direct to the OU. You then repay OUSBA interest-free and in full just before your module starts. 0% APR representative. This option could give you the extra time you may need to secure the funding to repay OUSBA.
  • Pay by instalments – OUSBA calculates your monthly fee and number of instalments based on the cost of the module you are studying. APR 5.1% representative.

Joint loan applications

If you feel you would be unable to obtain an OUSBA loan on your own due to credit history or affordability issues, OUSBA offers the option to apply for a joint loan application with a third party. For example, your husband, wife, partner, parent, sibling or friend. In such cases, OUSBA will be required to carry out additional affordability checks separately and/or collectively for both joint applicants who will be jointly and severally liable for loan repayments.

As additional affordability checks are required when processing joint loan applications, unfortunately, an instant decision cannot be given. On average the processing time for a joint loan application is five working days from receipt of the required documentation.

Read more about Open University Student Budget Accounts (OUSBA).

Employer sponsorship

Studying with The Open University can boost your employability. OU courses are recognised and respected by employers for their excellence and the commitment they take to complete. They also value the skills that students learn and can apply in the workplace.

Over 30,000 employers have used the OU to develop staff so far. If the module you’ve chosen is geared towards your job or developing your career, you could approach your employer to see if they will sponsor you by paying some or all of the fees. 

  • Your employer just needs to complete a simple form to confirm how much they will be paying and we will invoice them.
  • You won’t need to get your employer to complete the form until after you’ve chosen your module.  

Credit/debit card

You can pay part or all of your tuition fees upfront with a debit or credit card when you register for each module. 

We accept American Express, Mastercard, Visa and Visa Electron. 

Mixed payments

We know that sometimes you may want to combine payment options. For example, you may wish to pay part of your tuition fee with a debit card and pay the remainder in instalments through an Open University Student Budget Account (OUSBA).


Please note: your permanent address/domicile will affect your fee status and, therefore, the fees you are charged and any financial support available to you. The fee information provided here is valid for modules starting before 31 July 2026. Fees typically increase annually. For further information about the University's fee policy, visit our Fee Rules.

This information was provided on 04/06/2025.

Can you study an Access module for free?

Depending on eligibility and availability of places, you could apply to study your Access module for free.

To qualify, you must:

  1. be resident in England
  2. have a household income of not more than £25,000 (or be in receipt of a qualifying benefit)
  3. have not completed one year or more on any full-time undergraduate programme at FHEQ level 4 or above or successfully completed 30 credits or more of OU study within the last 10 years

How to apply to study an Access module for free

Once you've started the registration process, either online or over the phone, we'll contact you about your payment options. This will include instructions on how you can apply to study for free if you are eligible and funded places are still available.

If you're unsure if you meet the criteria to study for free, you can check with one of our friendly advisers on +44 (0)300 303 0069, or you can request a call back.

Not eligible to study for free?

Don't worry! We offer a choice of flexible ways to help spread the cost of your Access module. The most popular options include:

  • monthly payments through OUSBA
  • part-time tuition fee loan (you'll need to be registered on a qualification for this option)

To explore all the options available to you, visit Fees and Funding.

What's included

You’ll have access to a module website, which includes:

  • a week-by-week study planner
  • course-specific module materials
  • online activities and quizzes
  • audio and video content
  • assessment details and submission section
  • online tutorial access
  • access to student and tutor group forums.

You’ll also be provided with three printed module books, each covering one block of study.

You will need

A calculator with standard scientific functions.

Computing requirements

  • Primary device – A desktop or laptop computer. It’s possible to access some materials on a mobile phone, tablet or Chromebook; however, they will not be suitable as your primary device.
  • Peripheral device – Headphones/earphones with a built-in microphone for online tutorials.
  • Our OU Study app operates on supported versions of Android and iOS.
  • Operating systems – Windows 11 or latest supported macOS. Microsoft will no longer support Windows 10 as of 14 October 2025.
  • Internet access – Broadband or mobile connection.
  • Browser – Google Chrome and Microsoft Edge are recommended. Mozilla Firefox and Safari may be suitable.

If you have a disability

The OU strives to make all aspects of study accessible to everyone and this Accessibility Statement outlines what studying TM355 involves. You should use this information to inform your study preparations and any discussions with us about how we can meet your needs.

To find out more about what kind of support and adjustments might be available, contact us or visit our disability support pages.