What is a SIP line? SIP trunk vs SIP line difference
A SIP line is one phone connection that runs over the internet instead of a copper cable. It lets one device make or take one call at a time. A SIP trunk works differently. It is the internet connection for your whole phone system, bundling several of these connections together so multiple people can call in and out at once. This article explains both terms, and how to work out how many your business actually needs.
What is a SIP line?
SIP line meaning in plain terms: it carries one call at a time, in or out. SIP stands for Session Initiation Protocol, which is just the technical way of saying it is the method your phone system uses to start, manage and end a call over the internet. It is one single connection, built on that method.
Picture a small office with one shared phone number. If someone is already on the phone, a second caller gets a busy tone or goes to voicemail. That office is working with the equivalent of one line. A freelancer or a very small team often only needs one, because they rarely handle two calls at the same time anyway.
What is a SIP trunk line?
A SIP trunk line, or simply a SIP trunk, is the connection between your phone system and your provider. It bundles several individual lines together, so more than one call can run through the same connection at once.
Say your team has ten people who all take calls. With a SIP trunk, you can set up ten separate lines on that one connection, so ten calls can run next to each other without anyone hearing a busy tone. Read more about how this works on our page about SIP trunking.
SIP line vs SIP trunk: the actual difference
|
Aspect |
Line |
Trunk |
|
Connects |
One device |
Your whole phone system |
|
Calls at once |
One |
As many channels as you set up |
|
Best for |
A sole trader or single desk phone |
A team or office with several people calling |
|
Works with features like call queues, routing, auto attendant |
Not really |
Yes |
The two terms get mixed up a lot, because a SIP trunk is technically made up of them. So, when someone mentions a trunk with twenty lines, they mean twenty calls can run at the same time.
How many SIP lines do you need?
This depends on how many calls come in and go out at the same moment, not on how many people work for you. A shop with three employees who rarely call at the same time might manage fine with two or three SIP lines. A customer service team with call queues and callbacks usually needs more, simply because several calls stack up during busy hours.
A good way to check this is to look at your call reports over a normal week. If callers regularly hear a busy tone or sit in a long queue, you probably need more SIP lines. If lines sit unused most of the day, you can likely do with fewer.
SIP lines and SIP trunks with Xelion
With Xelion, you do not have to guess this once and live with it for years. You manage your SIP lines, call queues and opening hours yourself, and you see in real time how many calls are waiting and how many lines are in use. Everything runs in the cloud, so you are not tied to physical phone lines or extra hardware in a server room. You add lines as your team grows, straight from your desktop, your phone or your browser.
