What are analog trunk lines?

Understanding every aspect of a phone system will help you make the best decision when you’re ready to purchase and install. This knowledge will help you ask the right questions, recognize exactly what your business needs in a phone system, and facilitate a smooth relationship with the phone installer you hire. Let’s start with trunk lines and analog trunks.

A simple analog trunk line is a telephone circuit made of copper wire that runs from your local telephone company’s central office building to your business location. The telephone company’s central office building houses switching equipment that connects it to the public telephone network. This is sometimes called a local loop. Once installed, someone can call the phone number you subscribed to and the phone company can connect the call to you over the analog trunk line. A good point to remember with analog trunk lines is that a phone number is associated with a line. If you need more phone numbers, then your phone company will have to connect more analog trunk lines to your business.

Trunking refers to the concept that many users can access the telephone network by sharing a set of lines instead of each receiving one individually. Think of the trunk of a tree: all the branches share a trunk, and through this connection, they all have access to nutrients in the soil. Similarly, all the telephone extensions in your office have access to the public telephone network through a smaller set of analog trunk lines.

If you have a small office, each phone can be connected to the local loop and then receive its own phone line. However, if your office is growing and you need to connect many phone extensions to the public phone network, it just doesn’t make financial sense to pay for separate lines for each phone. In most circumstances, it is not necessary for all employees to be on the phone at the same time. Instead, by using the trunking concept, you can reduce the number of phone lines you pay for while still serving all the phones in your business. In fact, typical business phone systems are set up in ratios of 3-4 phone lines to 8 phone extensions.

If you are a small to medium business looking to use up to 10-15 incoming phone lines to connect your phone system, choosing analog trunk lines would be a great place to start.