Data T-1
A T-1 is a data transfer system that transfers digital signals at 1.544 megabits per second (quite a bit faster than a 56K modem, which maxes out at around 0.056 Mbps). Most small to mid-sized colleges and business have T-1 lines for their Internet connections. T-1's enable one circuit to carry either 24 voice, video or data conversations at 64 kilobits per channel
Because of the T-1's large bandwidth, hundreds of people can be accessing the Internet from one T-1 line. However, like all good things, too many people on one T-1 line can cause dramatic decreases in data transfer speeds. T-1 is equal to 24 channels and can be all data (cheaper), it can be all voice or it can be an integrated T-1. With an integrated T-1 you the customer can decide how may voice channels you need and how many data channels you need to meet your business needs.
Integrated and Fractional T-1's
Integrated and Fractional T-1's is a direct circuit from the local phone company to your business which carries both voice and data.
With an Integrated T-1 customers have the ability to configure each of the 24 channels for either voice Access or Internet Access. While that is not unique, the pricing module usually charges the same whether it is a voice or data channel.
With a fractional T-1 your business will have the ability to turn up on demand the channels that are not in use. This is a good feature for companies not quite ready for a full Integrated Access T-1.
PRI
PRI stands for Primary Rate Interface a PRI supports 24 channels with 23 B ( Bearer) Channels+1 D ( Data) Channel. The main difference between a PRI and T-1 is that a PRI ISDN has an out of band signaling on the 24th channel. In a T-1 signaling is carried in-band along with voice and data on each channel. Because of the out of band signaling of a PRI Each of the B Channels support a clear channel running at 64 Kbps providing the highest quality of voice calling.
PRI's are used with PBXs, key systems and routers for incoming and outgoing voice and data. Many corporations use PRI ISDN to capture the caller's information (caller ID) and send it to the telephone which displays the information and calls can then be answered or sent to voice mail.
T3
A T-3 is a point-to-point dedicated line that contains 672 individual digital channels, the equivalent of 28 T-1's. Each of the channels can transfer data at 64 Kbps. T3 lines are also called DS3 lines and in Europe they are called E-3's). The T-3 line, providing 44.736 Mbps, is commonly used by Internet service providers to connect to other carrier's backbone networks. Or large corporations with a private network that has large amounts of data communications between sites. The actual circuit is installed at the corporate headquarters acting as the hub.
A T-3 starts to be most effective if a company has at eight to ten multiple T-1's at the same site.
