PRI T1
Typical Applications: Small to Medium size businesses with heavy voice traffic, call centers, support centers, etc.
The Primary Rate Interface (PRI) is a telecommunications standard for carrying multiple DS0 Voice & Data transmissions between two physical locations. All DS0 Voice & Data channels are ISDN, and operate at 64 kbps.
North America and Japan use a T1 of 23 B channels and one D channel which corresponds to a T-1 line. Europe, Australia, and most of the rest of the world use the slightly higher capacity, E1, which is composed of 30 B channels and one D channel. Fewer active B channels (also called user channels) can be used for a fractional T1. More channels can be used with more T1s, within certain design limits.
In the Integrated Services Digital Network (ISDN), there are two levels of service: the Basic Rate Interface (BRI), intended for the home and small enterprise, and the Primary Rate Interface (PRI), for larger users. Both rates include a number of B-channels and a D-channel. Each B-channel carries data, voice, and other services. The D-channel carries control and signaling information.
The Basic Rate Interface consists of two 64 kbps B-channels ,and one 16 kbps D-channel. Thus, a Basic Rate Interface user can have up to 128 kbps service. The Primary Rate Interface consists of 23 B-channels and one 64 kbps D-channel using a T1 line or 30 B-channels, and 1 D-channel using an E1 line. Thus, a Primary Rate Interface user on a T1 line can have up to 1.544 Mbps service or up to 2.048 Mbps service on an E1 line. PRI uses the Q.931 protocol over the D-channel.
The Primary Rate Interface channels are carried on a T-carrier system line (in the U.S., Canada, and Japan) or an E-carrier line (in other countries) and are typically used by medium to large enterprises. The 23 (or 30) B-channels can be used flexibly and reassigned when necessary to meet special needs such as videoconferences. The Primary Rate user is hooked up directly to the telephone company central office.
Typical Applications: Small business start-ups, banks & financial institutions, professional offices, local government, hotels, colleges & universities, temporary placements where PBX is not practical (i.e., campaign offices)
To understand Centrex, you must first know what a PBX is. Short for Private Branch Exchange, a private telephone network used within an enterprise. Users of the PBX share a certain number of outside lines for making telephone calls external to the PBX. Most medium-sized and larger companies use a PBX because it's much less expensive than connecting an external telephone line to every telephone in the organization. In addition, it's easier to call someone within a PBX because the number you need to dial is typically just 3 or 4 digits.
Centrex is a PBX-like service providing switching at the central office instead of at the customer's premises. Typically, the telephone company owns and manages all the communications equipment and software necessary to implement the Centrex service, and then sells various services to the customer.
No switching equipment resides on the customer premise, as the service is supplied and managed directly from the phone company's exchange site, with lines being delivered to the premises either as individual lines over traditional copper pairs or by multiplexing a number of lines over a single fiber optic or copper link.
In effect, Centrex provides an emulation of a hardware PBX, by using special software programming at the central office, which can be customized to meet a particular customer's needs. As with a PBX, stations inside the group can call each other with 3, 4 or 5 digits, depending on how large the group, instead of an entire telephone number.
Centrex makes supplying separate exchange lines delivered to a site for use with a 1A2 Key System or similar, or PBX unnecessary. Instead, telephone extensions (called Centrex lines) are delivered directly from the local exchange to the user. Some customers, however, still like to use a key telephone system for a small office within the large corporate Centrex.
Unlike with a conventional PBX, it is a simple matter to have extensions at different locations while allowing them to function as if they were within the same building. Newer IP PBX systems also allow phones at any location with a WAN (Wide Area Network) or Internet connection to act as a local extension. Facilities such as Direct Inward Dialing (DID), where individual extensions are offered a direct and unique telephone number for incoming calls, are standard features in a Centrex environment. Stations may also be part of a hunt group, allowing for automatic distribution of incoming calls to two or more extensions.
With the high price of long distance service, many large companies have their own network of private lines crossing the country or to distant countries. Managing these networks of "Tie Lines" and connecting to them can also be an important part of Centrex. In many instances today,VOIP and MPLS have replaced Centrex to solve this challenge..
The Centrex customer is not restricted to using the features available to POTS customers, but can choose from a wide variety of special services and features. In fact, telecommunications companies generally offer numerous types of Centrex service, including "Packaged Centrex," "Centrex Data," and "Customized Centrex."
Packaged Centrex customers could be offered a fixed set of features in package "A", a different set of features in package "B", and so on. These packages are typically offered at a relatively low cost as little or no customization is permitted, minimizing the operational costs of programming and maintaining the services for the telephone company.
Centrex Data services can provide relatively low speed (56 and 64 kbps) data services utilizing the circuit-switched telephone network. Although they are now overshadowed by the Internet and other data networks, Centrex Data services can offer very flexible and wide-reaching network configurations since connections can be made almost anywhere within the reach of the telephone network.
Customized Centrex is the most flexible (and most expensive) Centrex service, as it offers a highly customizable set of options that require specialized programming and troubleshooting skills to maintain. A typical Customized Centrex setup will allow 4 digit dialing between "locals" (perhaps even if they are located in different parts of the city), customized routing through the telephone network (such as Least Cost Routing or Time of Day Routing), and customized codes for invoking features.
Long Distance
Typical Applications: Connection outside of local calling area
Long Distance is the service over phone lines where the traffic is switched by your local phone company to the long distance provider selected. Typically this is long distance service provided on regular phone lines (POTS.)
Long distance services can be delivered via a "Dedicated Long Distance T1" (a dedicated digital communication link that offers 1.544 Mbps). This solution is used for carrying long distance traffic over 24 (64K) channels.
Another option is "Dedicated DS3 / T3 Long Distance" (heavy-duty line for extremely high bandwidth connections, capable of carrying dedicated digital communications at 44.7 Mbps). This option is used for carrying long distance traffic over 672 (64K) channels.
It can often be confusing as to when is the right time to use a traditional POTS for long distance as opposed to when it makes sense to upgrade to a T1 (or a T3). Give us a call and one of our experts will be glad to walk you through this often difficult, yet important decision.
Integrated T1
Typical Applications: Replacement of POTS and DSL for Small to Medium size Businesses requiring increased bandwidth, bundled solutions
Integrated T1 (also called channelized T1) is a digital carrier modulation method in which a T1 line is divided into 24 channels, each having a maximum data speed of 64 thousand bits per second (Kbps), and each capable of supporting a unique application that can run concurrently with, but independently of, other applications on different channels.
T1 is the most commonly used digital carrier method used in the United States, Canada, and Japan, carrying 24 pulse code modulation (PCM) signals with time-division multiplexing (TDM) at an overall rate of 1.544 million bits per second (Mbps).
Integrated T1 has become popular with businesses because of its flexibility. It allows an enterprise to run several services, such as Local Telephone, Long Distance, Internet, and Voice over IP (VOIP) over a single circuit at the same time. Integrated T1 should not be confused with fractional T1. A fractional T1 line is leased to a customer at a fraction of the data-carrying capacity of a conventional T1 line, and at a correspondingly lower cost.
Conference Bridges
Typical Applications: Web Conferencing, Decentralized Board & Planning Meetings, Travel Budget Reduction
Conference Bridging refers to a wide range of conferencing solutions that enable a business to reduce corporate expenditures while improving productivity. From a basic two-venue meeting to a nationwide videoconference, conference bridges enable companies to efficiently connect people at a fraction of the cost of business travel.
Regardless of the meeting type, solutions can address virtually every business requirement ranging from instant multi-channel conferencing to critical event planning services. With no obligation and a low per-minute rate, companies can have access to incomparable conferencing capabili
ties including:
Conference Recording & Playback
Project Code-Based Billing for Improved Financial Allocation
Toll-Free Dial-In Numbers for International Participants
Operator Assistance
Online Call Management Tools to Schedule, Present & Archive Your Call on the Web
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