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What Is Q SIG? How Does Q Signaling Works

Q sig/Q signaling is a telecom technology that allows communication across various equipment types like PSTNs, PBXs, and VoIP gateways. The Q SIG, an ISD-based signaling protocol, connects all Private Branch Exchanges (PBXs), allowing users a seamless communication experience to enhance customer satisfaction and experience.

In a vast network, It facilitates a robust signaling system between different voice communication platforms. Q signaling is essential for generating and managing connections and ensuring efficient data transmission and network reliability.

This article will delve into the Q sig technology, focusing on its history, features, working criterion, advantages, utility, and future growth and expansion prospects.

What is Q SIG?

The Q Sig is a signal protocol used for controlling calls between two different pieces of equipment in telecommunication. It works within a Private Integrated Services Network by seeking help from connection-level Q9.31 and application-level Rose.

It’s quite flexible and easy to use with all Private Branch Exchanges. It uses ISDN as a physical link layer by enterprise voice. You can take it as a bridge between two Private Integrated Network Exchanges.

History of Q Signaling

Q signaling has now become an ISO standard; that’s why a solo company can not own it. ETSI developed it in 1990, and the main objective of this type of signaling is to enable communication between private branch exchanges.

It was designed to connect the different PBXs for communication and information sharing. Different features have been installed in it, like call setup, conferencing, call diversion and call forwarding. You can also have additional features like call hold and call waiting.

Another interesting fact is that PBXs are capable of exchanging messages with each other. For all PBXs, using Q signaling to communicate and share data is compulsory.

In its early days, it was widely popular in Europe and adopted by mange large scaled PBX deployments. In recent years IP-based telephony systems have become excessive in use that has declined Q signaling.

How Does the Q SIG Control Protocol Model Work?

It provides a set of signaling messages used by the PBXs to communicate with each other through calling or sharing data. In simple words, it establishes a common digital signaling method for different PBXs to share messages over it.

That’s how two different PBXs come in contact with each other and communicate. Its signaling messages are based on ISDN Q.931 protocol. Along with that, it provides all of the additional features mentioned above.

Whenever two PBXs want to communicate, they must build a Q signaling channel to make it possible. They can now share messages, calls, conferences, or forwarding when establishing a network. It’s a private network used by many PBXs to communicate.

The QSIG/PSS1 sends status messages to both PBX parties to let them know the current signaling situation. That’s how its users will be familiar with all the errors and plan solutions accordingly. It is considered the standardized way of communication between PBXs.

Features of Q SIG

Q Signaling were designed for Private Branch Exchanges ( PBXs ) to contact each other to share messages, files, and conferences. It has different features that could benefit all its PBX users.

Let’s explore the features of Q signaling!

Call Setup: Q SIG allow all PBXs to build a connection for communication and making and receiving calls.

Call Transfer: Q signaling allows users to transfer calls to other numbers and extensions.

Call Forwarding: Q Sig allow users to transfer calls from one extension towards another or any external number.

Call Diversion: Q signaling users can transfer calls towards another extension or number if the destination place is busy.

Conference Calls: Q signaling allows the users to call multiple users at a time to meet or discuss something.

Additional Services: Along with its features, you can have additional services like call holding, call waiting and call park.

Status Messages: Q SIG protocol allow exchanging messages about the signaling status; if there is any error in signaling, it will let the PBX users know and resolve the issues.

The Q Sig provide a standardized way of communication with their users, along with all the updated features.

Advantages of Q Signaling

Q signaling provides many advantages to all of the PBXs and the rest of the Integrated Services Digital Networks ( ISDN ). You may find numerous benefits to ensure your communication is unbroken and errorless.

Let’s explore the advantages of Q SIG.

1. Advance Call Features

Q signaling provides updated features like call forwarding, call waiting, and three-way calling. These features enhance the productivity of the organizations.

We must update any software’s calling features because the old features may not make your work more productive.

2. Call Set Up

Q SIG protocols build a network-like bridge to let the Private Branch Exchanges connect and communicate. They can share files and meetings by having as many users as possible.

3. Scalability

Both of these protocols provide large and small user counts accordingly. If your business has a large number of employees, then you can enhance its capabilities accordingly.

On the other hand, if they aren’t large in number, then just change their usability accordingly. That’s very attractive for all the organizations; they don’t need to waste money on having extra users to communicate with.

4. Security

Both protocols provide trustworthy security and ensure all of the PBXs that their communication will be secure and encrypted. You may always need authentication to ensure the relevant access is official. All unauthorized access will be denied.

Disadvantages of Q SIG

Q signaling has a lot of benefits for its users, but along with that, there are still a few disadvantages which many of you may face.

So let’s have a deep dive into it!

1. Limited Vendor Availability

Q SIG isn’t used at a vast level, so it would be difficult for the organizations using this communication tool to have experts who know its better use. And you might not be able to find its equipment. That’s the most common limitation of the Q SIG protocol. 

2. Limited Calling Features

There are a few limitations in its calling features whenever you make calls to a non-Q SIG network, then there will be a few limitations for you. You may not be capable of making calls in the same way as with the Q SIG network. 

3. Limited Obtainability

This signaling service isn’t available in many regions, and organizations can’t use its benefits. In those areas, they must use alternative signals to communicate with the rest of the Private Branch Exchanges. 

4. Expensive

QSIG is considered one of the most complex signaling protocols, which needs experts to handle, and that’s hard to handle. Then things will be difficult to handle for all of the new organizations.  

Uses of Q SIG

Q SIG is a signaling protocol used for communication between PBXs. It’s considered one of the old ways of communication. Through this method, a PBX builds a signal connection with the other PBXs for communication.

Let’s explore its uses, which all the respective companies can have!

1. Interconnection Between Two PBXs

Whenever two or more private branch exchanges want to contact each other for communication, they use the Q SIG signaling protocol. All of the employees of these organisations can communicate with each other from different locations

2. ISDN Services

 All of the organizations using Q signaling are capable of sharing data, files, videos, voice notes and the rest of the things, along with calling and conferencing. It plays a very pivotal role in digital communication networks.

3. Calling Features

This signalling protocol provides many updated calling features to all its users, like call forwarding, call waiting, and call hold. These features make your work more productive for all private branch exchanges.

Future of Q Signaling

All things keep changing with time. The same applies to Q signaling; it will keep improving with time. Its features, like calling and other communication functions, will be kept on changing.

New features and functionalities will make things easier for all respective organizations using it. They are analyzing all the major issues and limitations their customers face and planning new amendments accordingly to resolve them. So its users should stay tuned and wait for the best days.

We hope its new amendments will surprise its users and give them better functionalities to make your work more productive.

Final Words - Q Sig

Q SIG is a signaling protocol to build connections between Private Branch Exchanges for communication and data sharing. In this discussion, we have interpreted all of the worth-telling information for your better understanding of Q signaling.

All PBXs used to connect through this signaling protocol; one private branch sends signals to connect the respective private branches, and all of their employees can have discussions and meetings to make plans accordingly.

They are making many plans to make this Q signaling more interesting and productive for all its users. QSIG are the same protocols used to build a connection between two different Private Branch Exchanges. This signaling protocol gives status updates through messages. It lets its users know about the current situation of the signals. If there is any error, you may receive an update through a message to make changes accordingly.  


Zayne Z

Meet Zayne VoIP Blog's dedicated Content Researcher with 5+ Years Experience. Passionate about VoIP technology, he delivers accurate, engaging articles, keeping readers informed on industry trends with excellence.