PRI
Primary Rate Interface is a switched service delivered over a T1
connection. If someone were to say “I want to order a PRI to location
X,” or if someone were to say “I want to order a T1 to that SAME location
X.” there would not be enough information to assist the customer in finding
what they are looking for. The customer would need to disclose from where
and to where they need their T1. By simply asking for a T1, nothing is understood
or implied about where or what the circuit would be used for. A T1 can be
used to truck data at the rate of 1.544 Mbps from one location to another.
With channel banks and appropriate DS0 level cards, a T1 can be used to
truck up to 24 separate and distinct DS0 signals (analog data, analog voice,
or Digital Data Service) from one location to another.
A T1 can be used to connect one location to an ISP Internet Edge device
to connect a customer to the World Wide Web. What is being requested is
a connection to a trunk side module capable of ISDN protocol to a Telco
switch delivered to location X via a DS1 rate (T1) circuit. You can use
T1 for voice and/or data depending on the equipment you have at each end.
They are basically just providing the "Pipe" and it is up to you
what it is used for.
As quoted above, a T1 is just a 24-channel circuit that can be used for
multiple things. A PRI is a protocol that uses the 24th channel to control
what the other 23 channels are used for. A T1 has 24 channels using 56K
for data and 8K for signaling. A PRI has 24 channels and uses 23 for data
and the 24th for signaling. In addition, you can break down the channels
on a T1 for different type of service.
On the PRI all 23 channels have to be the same.
PRI is a different protocol to be used with voice services over the T1 line.
Where as a T1 line can also be used for voice but without using the PRI
protocol and probably using different equipment at the other end to get
the dial tone.
There are a lot more technical details dealing with ISDN lines. The simplest
approach to finding the best solution is to request infrastructure design
and rate quotes for PRI and/or T1 voice
service comparing providers available in your area.
