What exactly is Primary Rate Interface (a.k.a. PRI)?

PRI is a type of ISDN connection, that is typically used for connections between a PBX (private branch exchange a.k.a. a telephone exchange operated by customer of telephone company) and a CO (central office) or IXC (inter exchange carrier a.k.a. long distance telephone company). PRI uses the public telephone network to carry digital signal for all your voice and data communications needs.

PRI connections are characterized as:

• 23 channels supporting voice, data, and video services that can be easily combined or allocated for your own desire
• A 24th channel to support signaling between your equipment and the network
  

With a PRI service you will be able to:

• Combine voice and data communications and have the ability to upgrade the capacity when desired.
• Re-allocate capacity at any time.
• Expect 1.54Mbps capacity.
• Carry signaling information over a separate channel and speed up the process of your calls
• Any channel can carry any type of connection, eliminating single-purpose trunks such as Direct Inward Dial, Direct Outward Dial and dedicated video or data lines
• Allocate more channels to an application in multiples of 64 Kbps
• If data is your main communication need, the inward data option supports analog, digital data calls, and a digital data only option

A ISDN PRI service has the following benefits:

• If your company's primary needs are voice communications, replacing standard single-purpose trunks with PRI service can result in significant savings
• Increase the speed and flexibility of LAN access without dedicated lines
• Bandwidth on an as needed basis

These features and characteristics makes the ISDN PRI a very stable and reliable connection.