What Is Q SIG? How Q Signaling Works In Telecommunication 2024

What Is Q SIG (Q Signaling)

Q SIG or Q Signaling is among these technologies that are designed to enable communication between different types of equipment, such as PSTNs, PBXs and VoIP gateways. This technology was created to address the limitations of earlier signaling protocols (ISDN and SS7).

You may have heard about this technology but do not know how it works and benefits telecommunication companies.

Here in this article, we will explore the basics of Q SIG, how it works in telecommunication, and its capabilities and deployment.

Stay with us to get all this information to understand whether Q SIG is beneficial for your telecom company.

What Is A Q SIG?

Q SIG is a signaling protocol that controls calls between different types of equipment in a telecommunication network. It is based on ISDN and communicates signals between private branch exchanges (PBXs) within a Private Integrated Services Network (PISN) with the help of application-level ROSE and connection-level Q9.31 protocols.

Although this protocol is based on the ISDN User Part (ISUP) of the SS7 protocol, it is more flexible and easier to use. It works by using ISDN as the physical link layer in the exchanges and is typically used in enterprise voice or integrated service networks.

The Q reference shows that this protocol derives its name from the formal dividing point between two Private Integrated Network Exchanges.

Who Invented The Q Signaling Protocol?

Q SIG was first created by ECMA international and then adopted by the European Telecommunication Standards Institute (ETSI). This protocol is formally defined as an ISO standard, so a single company cannot own it. It provides maximum operability between communication platforms created by different platforms.

How Does Q SIG Work?

Q signalling is typically deployed in two layers one is the basic call, and the other is the generic function. The basic cell layer is used to define how calls between two or more PBXs take place. While the generic function layer takes care of supplementary services such as call intrusion, call forwarding and line identification.

This protocol can be implemented on a network without the users knowing which switch their phone is using. It is possible to deploy Q SIG protocol independent of the underlying transport technology, and it can be deployed on both IP networks and leased phone lines.

It works by providing a standard interface for PBX systems. This protocol allows PBX systems to communicate with each other with the help of a common language.

This common language is used to send and receive signaling information to control the communication between PBX systems. With the help of this protocol, telecom companies can provide many services, which include:

1. Call Initiation And Termination

Q SIG is a powerful signaling protocol providing services that initiate or terminate calls between two or more PBX systems. It enables PBX systems to communicate with each other efficiently and reliably.

2. Call Forwarding

Another service that Q SIG provides is call forwarding which means if a call is not answered by one PBX system, it can be forwarded to another PBX, ensuring no call is missed.

3. Call Transfer

Another service Q SIG offers call transfer between PBX systems. It means that a call initiated from one PBX can be transferred to another PBX, ensuring that appropriate persons answer calls.

Q Signaling In the Telecommunication Networks

Q Signaling is a protocol used to control calls between different types of equipment in a telecommunication network. When someone initiates a call, the calling party’s equipment sends a setup message to the party’s equipment using Q Signaling.

Then the equipment on the receiver’s side responds with an alert message, and the calling party’s equipment sends a connect message to establish a call. It is how Q SIG works and provides supplementary services.

Benefits Of Q SIG

Q SIG offers numerous benefits to the telecommunications industry, some of which are as follows:


As we described earlier, Q SIG Provides a standard interface for PBX systems enabling them to communicate regardless of the model or manufacturer of the system. It means that PBX systems created by different manufacturers can communicate with each other without any hassle. It is a significant advantage for companies using different types of PBX systems.

Increased Productivity

With Q SIG, businesses can provide a better communication system to their employees and improve their productivity. Using standard interfaces allows companies to integrate different types of PBX systems, which can improve the efficiency of communication between companies and overall productivity.

Cost Savings

By using a standard interface, businesses can save money they have to spend on integrating different systems otherwise. With Q SIG, companies can use different PBX systems but still be able to communicate with each other.

Additionally, Q SIG is designed to be more efficient than other signaling protocols, which helps in reducing setup time and improving call quality.

What Are The Features And Capabilities Of Q SIG?

Q SIG provides a wide range of call control features and supplementary services. Some important call features include call setup, call hold, call waiting, and call transfer.

Supplementary services offered by this protocol include an automatic callback, caller identification and call forwarding.

In addition to these basic features, Q SIG also offers some advanced capabilities, including multi-party conferencing, support for virtual private networks and intelligent network services.

Q SIG and VoIP

Q SIG can also be used in conjunction with VoIP (Voice Over Internet Protocol) to enable communication between traditional telephone systems and IP networks. It can be used to control calls between different equipment in a VoIP network, including softphones, VoIP gateways and IP phones.

Integrating VoIP with Q Signaling can help you improve call quality, reduce latency and provide high-quality services to your customers.

Q SIG Deployment

Q SIG can be deployed in different ways depending on the requirements of your network. In traditional phone systems or networks, Q SIG controls calls between PSTNs and PBXs.

On the other hand, in IP networks, it is used to control calls between different equipment of VoIP networks and to enable communication between VoIP and traditional telephony.

Q Signaling can be deployed by using a variety of technologies such as IP, TDM (Time Division Multiplexing) and ATM (Asynchronous Transfer Mode).

What Is The Future Of Q Signaling?

If we look into the future of Q Signaling, it is likely to evolve and improve. It is expected that new versions of this protocol will come on the market that will be able to provide more flexibility, advanced capabilities, and improved interoperability.

As telecommunication companies continue to evolve, Q SIG is likely to remain an important part of it, enabling communication between different types of networks and equipment to support the industry’s ongoing growth.

Conclusion - Q SIG (Q Signaling)

Q SIG is a powerful signaling protocol that has revolutionised how different types of equipment communicate in telecommunication networks. Its flexibility, ease of use, and advanced capabilities make it an attractive choice for telecommunication providers looking to improve their networks.

Its ability to support various equipment types and supplementary services makes it a good choice for organisations looking to implement unified communications solutions.

As the industry continues to evolve, Q Signaling is likely to remain an important part of the landscape, enabling communication between different types of equipment and networks and helping to support the ongoing growth and evolution of the industry.

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