Recently, you may have been hearing a lot about T1 PRI services, but what exactly are they? T1 PRI can be best explained by separating these two individual aspects.
The term PRI refers to Primary Rate Interface. This is provided by the ISDN, or Integrated Services Digital Network. ISDN provides two basic levels. The first, and most common, is known as BRI, or Basic Rate Interface. The second is known as PRI, or Primary Rate Interface. Both of these utilities are a method in which many voice and data transmissions can be sent and received over a single fiber-optic cable.
BRI provides 3 independent lines that can be used for voice or data. PRI is more robust and uses 24 channels to support individual threads, making it more geared towards businesses or other situations that require many voice lines or larger quantities of bandwidth to be delivered.
T1 service is actually not a service at all, but should be thought of more as hardware. This type of thread provides the necessary means for PRI service to be delivered to a location. In short, PRI is the actual service, while T1 is the hardware used for delivery.
A T1 line consists of 24 channels, which can each be used to serve a different purpose. All of them may be used to deliver 24 individual phone threads to a location, or may all be used to deliver bandwidth for data networks and Internet connections. Alternatively, the 24 channels may be split up and dedicated to voice or data in any combination, such as 12 lines of voice and 12 lines of bandwidth.
When used for bandwidth, each channel is capable of delivering 64 Kbps of data, meaning that a T1 line fully dedicated to bandwidth will provide 1.54 Mbps of data.
The real beauty of the utility is that the customer basically leases the T1 line itself. This means that the it is dedicated to this customer alone, providing reliable bandwidth for networking or Internet use at all times. This is as opposed to traditional methods of data delivery, in which lines are reused over and over and shared by several users, decreasing the quality of the connection. This is a process known as "switching" and can significantly decrease the quantity and quality of bandwidth being delivered.