Integrated Services Digital Network

Integrated Services Digital Network

Integrated Services Digital Network (ISDN)

What is ISDN

ISDN, or Integrated Services Digital Network, is a circuit-switched telephone network system that transmits data as well as voice over a digital line. Alternatively, it can also be viewed as a set of communication standards used for data transmission, voice transmission, and signalling.

Traditional connections are notorious for delivering slower speeds and lower quality than ISDN connections. As speeds and connections improve, data transmissions become more reliable.

ISDN consists of multiple digital channels over a traditional copper telephone line. The channels run concurrently on one copper line, allowing multiple phones to use one physical network line to make and receive calls simultaneously.

What are the types of ISDN networks

There are 2 main types of ISDN: BRI or PRI.


This is a type of ISDN connection for voice-grade telephone services known as BRI, or Basic Rate Interface. It consists of 2 B-channels (bearer channels), each running at 64 kbits/s, as well as 1 D-channel (delta channel), running at 16 kbits/s.


PRI stands for Primary Rate Interface and is used to transport multiple Digital Signal Zero (DS0) services and data between the ISDN network and an end-user. Businesses, offices, and enterprises commonly use PRI.

Other options for ISDN

VoIP is replacing traditional telephone systems. The service allows users to make phone calls over the internet without requiring a physical telephone line.

The traditional ISDN line offers little flexibility. Businesses that use ISDN are bound by physical locations. For remote working and building expansion, companies are increasingly looking for cloud-based systems that are scalable and flexible.

Currently, around 40% of businesses use VoIP to fulfil these requirements, which makes IP technology a more suitable choice.

If you already have ISDN lines and don’t want to commit to an on-premise phone system, choosing a Berry Telecom VoIP phone system is the best option for you.

There’s no need for any physical lines or hardware (other than configurable handsets), and everything is looked after and managed by us.

Switching from ISDN to VoIP is extremely simple. First, you need to find out what your business needs/want and how many phone extensions you’ll need. If this number changes, your provider will add and remove it as necessary.

What impact will switching from ISDN to VoIP have on your businesses?

You still have time to change your ISDN line if you are an existing business with an ISDN line. In case your business is just getting started, you should go straight for IP technology – since ISDN lines cannot be purchased anymore

Regardless of whether you choose VoIP or SIP to make the switch, you will see a positive impact on your business communications as well as your business overall. Here are the benefits of making the switch to IP:

  1. Cost-effective
  2. Accessibility
  3. Scalability
  4. Control
  5. Voice Quality
  6. Call forwarding
  7. Call waiting
  8. Voicemail
  9. Caller ID
  10. Three-way calling

Berry Telecom provides the best VoIP service in the UK. Call us on 0330 222 0332 or email us at to discuss your business solution needs.

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