PRI Service

Another type of T1 is an ISDN-PRI (Integrated Services Digital Network-Primary Rate Interface). Often this is referred to simply as a PRI. An ISDN PRI T1 might be called a T1 on steroids. The difference is that a PRI uses a D channel (data channel). A PRI uses one of the 24 channels available in a T1 as the D channel. This channel carries the customer call information and control signals rather than an actual call. The PRI phone service has 23 B-channels, or bearer channels, and one D-channel, or delta channel. The delta channel is responsible for the controls and signals for the 23 bearer channels that are used to transmit voice and data information through the lines. What this means to you, the customer, is a PRI can provide the information for Caller ID and screen pops, customer information and history that “pops up” on a computer screen prior to an incoming call being answered.

PRI’s are generally used for larger businesses or customers with more modern phone systems. Customers requiring DID (Direct Inward Dial) capabilities most often use PRI service. PRI gives the end user the ability to deliver individual direct numbers to every employee in the business without having to pay a fixed cost per line like with analog phone service. With a PRI you can get as many DID’s as you need without increasing the cost of the service significantly. PRI phone service with T1 lines can also handle the large telephone systems of call center operations and large corporations. The 23 bearer channels replaces the same amount of separate analog phone lines, and each PRI B-channel can be easily assigned to meet the specific tasks of its users, such as for fax machines, Internet and video conferences.

Direct Inward Dial can also enhance a customer’s experience by having them go directly to the appropriate department or person. Without DID numbers everyone has to dial the main number and then calls are distributed from there. This can cause bottle necking and placing customers on hold. If you are using an auto attendant which picks up the calls on your main line, DID’s allow you to bypass the general greeting instructions like press 1 for sales, 2 for a company directory, etc. The call terminates right to the person’s DID that you called.

PRI service is also available in a dynamic offering which can also save companies money. In the past if you wanted internet on a PRI it either wasn’t available or it had to be channelized in fixed amounts of speed like 256K, 384K, 512K, 768K, or 1024K. This would also limit the available channels for outgoing and incoming calls. For example a 768K would only leave 11 channels for voice. With a dynamic PRI you can get up to 1.5 MBPS of internet when there are no channels of voice being used. Many of the carriers we work with will guarantee 768K of internet even when all 23 channels of the PRI are in use. Say goodbye for the need to have a PRI and separate internet T1!