ISDN stands for Integrated Services Digital Network. It is a set of communication standards that allow for the digital transmission of both voice and data over a single line connected to the public switched telephone network. At its inception, the primary purpose of ISDN was to create an end-to-end digital telephony network. However, it was overtaken by more competitive technologies by the time it was released.

To better understand ISDN, let’s look at its history, how it works, and its usage around the world. We’ll also look at some alternatives you can consider for your business.

As mentioned earlier, the purpose of ISDN was to create an end-to-end digital telephony network. Digital signals could carry more information per second than analog signals, and digital transmission doesn’t compromise voice quality even over longer distances.

By the 1970s, the core telephone network in the western world had transitioned from analog to purely digital systems. Phone offices connected via the public switched telephone network (PSTN) were now using digital signals to transmit their voice and data. However, the wires connecting users to their corresponding phone offices were still analog. These analog wires are referred to as “the last mile”.

Unfortunately, the last mile comprises 99% of the total wired connections in the telephony network. It would have been too expensive and difficult to change them all to digital. ISDN was conceived as a way to digitally transmit data between users and phone offices without replacing the existing analog connections.

However, its long standardization and development process saw that more advanced and competitive technologies were already around by the time ISDN was rolled out. Although it found its niche in businesses and broadcasting industries, it did not achieve the high consumer demand and commercial success expected of it.

An ISDN line has two types of channels:

• Bearer channel (B-channel) - As its name suggests, the B-channel bears the main data (eg. voice, video, etc.) and transmits it from one point to another.
• Delta channel (D-channel)n - The D-channel is used for signaling and control. It carries information about the data being transmitted (eg. session information, signal errors, etc.)

A standard ISDN line is made of at least two B-channels and one D-channel. This allows ISDN to maintain multiple connections simultaneously and transmit different kinds of data at the same time. The integrated services in ISDN refer to its ability to integrate multiple types of communication services (such as video, audio, fax, etc.) in a single line or network.

The are two types of ISDN lines: BRI and PRI. They are classified based on their uses, number of their channels, and capacity. Let’s take a look at both more closely below.

BRI (Basic Rate Interface)

BRI is the ISDN standard, lower-tier option, making it optimal for home or small business use.

It is made up of two 64 kbit B-channels and one D-channel that supply 16 kbps. The speed of BRI ISDN networks is capped at 128 kbps. This makes it faster than its dial-up predecessors which were capable of only 56 kbps, but not as fast as DSL.

PRI (Primary Rate Interface)

PRI is the standard service option for medium and large businesses due to its higher speed capabilities. It’s capable of carrying Digital Signal Zero (DS0) services and data from the telephone network to a user and vice versa at a T1 speed of 1.544 mbps. This can go up to 2.048 mbps on E1 (E-carrier system).

PRI has 23 B-channles and one D-channel, allowing more simultaneous transmissions of voice, data, files, and video on a single line. It enables multiple user functions and duplex capabilities, potentially doubling the speeds of the basic option.

ISDN already faced stiff competition from technologies that offered faster speeds and more advanced features even by the time it was released in the 1980s. Still, it remained a core telephony technology in the industry for many years, and it found a niche in broadcasting and video conferencing. However, as telephony technology improves, ISDN has become obsolete over time, causing telecom providers to announce that ISDN will be phased out by 2025.

With ISDN and PSTN soon to be obsolete, businesses have either already made the switch, or are in the process of doing so. According to some providers, ISDN lines will no longer be available for purchase by 2023, so it’s time to start thinking about alternative options before the switch-off starts.

If you’re interested in looking for alternatives, here are our recommendations.

Making the switch from a legacy system to a digital communications solution is relatively stress-free. What matters most is that you make the right choice for your business’ needs.

There are two principal options to choose from:

• VoIP: For companies who want to buy a whole new business phone system (I.e., a hosted PBX system)
• SIP: For companies who want to keep their on-premises phone system

What is VoIP?

Voice over Internet Protocol (VoIP) allows users to make calls and transfer data over an internet connection rather than a landline or mobile network. It converts audio signals into digital signals (data packets) which are then sent to the receiver over the internet, all in the space of milliseconds.

All users need is an internet-enabled smart device (like a computer or softphone) and a stable internet connection to make calls from anywhere, anytime.

Whereas traditional systems have severe limitations as to the devices they can operate on, there are a range of devices that support VoIP communications. These devices include computers, laptops, softphones, and traditional phones connected to an ATA (analog telephone adapter).

In the wake of broadband, internet protocols have exploded in popularity amongst consumers and businesses alike. The VoIP phone system looks set to completely replace the traditional phone system, which is hardly surprising when you take a look at the benefits of VoIP.

The Advantages of VoIP

The number of devices that support internet calling is a serious advantage, but it is far from the only one:

1. Cost-Effectiveness

VoIP boasts both initial and long-term cost-effectiveness. Because connections are made over a VoIP network system rather than copper wiring, it negates the need for businesses to purchase a high quantity of individual telephone lines. This saves startups a significant amount of money, especially when service providers like 8x8 offer their services to help get businesses up-and-running efficiently.

When it comes to long-term value, VoIP telephony solutions incur significantly lower costs thanks to unlimited long-distance calling, domestic calling, business SMS, and other features.

2. Higher Quality Calls

All you need is a stable internet connection to get flawless sound quality on your calls. With most businesses already prioritizing bandwidth, call quality is usually the same, if not even better, than what a traditional landline service can provide.

3. Flexibility

As long as you have a broadband internet connection, there are no geographical limitations to a VoIP service. There’s no need to install new lines or liaise with providers to transfer numbers to new locations at high costs.

Naturally, this flexibility has empowered businesses to expand to different geographical markets and explore remote working opportunities with ease.

4. Scalability

IP solutions were created with scaling and future-proofing in mind. There’s no need to install new physical lines and you can add new users in minutes, making expansion much more feasible for small businesses.

5. Disaster Recovery

Because legacy systems operate over physical phone lines, they are much more vulnerable to hardware malfunctions or natural disasters. On the other hand, VoIP connections are operated by a third-party provider in a hosted location, meaning that you can access your data in the event of a disaster as long as you have an internet-connected device.

6. Advanced Call Features

Hosted IP PBX solutions like 8x8 offer a range of business telephony features that grant businesses increased agency over their internal and external communications. These features either come included with your subscription or can be added on as and when you need them.

Here are just a few of the best:

• Auto attendants
• Dynamic caller ID
• Extensions
• Call waiting, transfer, and recording
• Unified communications
• International call forwarding
• Call analytics
• And more

ISDN vs SIP Trunking: What is SIP?

Session Initiation Protocol (SIP) is one of the possible application-layer protocols used for VoIP communications. Essentially, it is a set of rules that allows you to initiate, define, and terminate data and voice transfers over an internet connection. SIP trunking is the method of using your pre-existing PBX system to facilitate this connection.

SIP trunking is an increasingly popular alternative to traditional telephony systems, for businesses wishing to keep their on-premises hardware. Because it uses virtual lines rather than physical lines, it is a flexible solution for small and large companies alike.

Businesses with complex PBX systems and high call volumes, like customer support or outbound call centers, are particularly suited to SIP and SIP trunking services.

Advantages of SIP Trunking

Many of the advantages we gave for using VoIP-based telephony solutions naturally apply to SIP trunking, too. However, there are a few extra benefits of using an on-premises PBX solution with SIP trunking.

1. Cost savings - Allows companies with complex systems and applications to consolidate technologies for unified communications.
2. Higher security - All of your data is stored on your on-premises, centralized system, rather than a hosted location supplied by your provider. This grants you increased security options and more control over your sensitive data.
3. Multimedia communications - SIP trunking allows you to transmit voice, video, and text data.
4. Advanced cloud application integration capabilities - Many providers, like 8x8, also offer built-in business application and software integrations.

Should I Switch to VoIP or SIP?

Here are some key questions to ask yourself before making the switch:

• Do I want to invest in a whole new phone system or keep my current setup?
• Can my current bandwidth support VoIP, or do I need to change providers?
• Will I be making a lot of international calls?
• Can I support the additional security requirements?
• What features are the most important for my business’ needs?

Now is the best time to make the switch from an ISDN to a VoIP solution, and not just because you won’t have a choice in the near future! Up-to-date solutions offer a wide range of benefits to suit a variety of different business sizes, budgets, industries, and needs.

What’s even better is that VoIP providers strive to continuously upgrade and innovate their technology and services, so who knows what type of communication possibilities are just around the corner.

With 8x8’s solution for small businesses, you can enjoy unlimited domestic calls, international calls, video conferences, and business SMS. As well as advanced call management features to elevate your business communications. Chat with sales or schedule a meeting with a specialist to discover all that 8x8 has to offer.

FAQs

What is the Difference Between ISDN and PSTN?

Introduced in the late 1800s, PSTN is the traditional circuit-switched network used for analog voice communication. Its use of underground copper wires was revolutionary at the time, cementing it as the leading telecommunications network for the best part of a century.

However, it was upstaged in call quality and service features by the soaring popularity of digital lines in the late 1900s.

What is the Difference Between the Internet and ISDN?

The internet is a global, packet-switched network of interconnected computers. It uses standardized communication protocols (TCP/IP) to facilitate worldwide communication and resource-sharing.

On the other hand, ISDN is a circuit-switched telephone system that can be thought of as a development of the POTS (Plain Old Telephone Service).

What Are the Differences Between ISDN and DSL?

ISDNs and DSLs are both digital transmission systems that work over the same network, but there are a few key differences.

Primarily, a Digital Subscriber Line (DSL) doesn’t need to dial up to a number, nor does it require installation. Instead, it uses pre-existing telephone lines along with a modem to provide an “always-on connection” that grants significant speed advantages.