Local Voice T1s provide local calling area access with up to 24 channels of utilization per T1 (DS1). These T1s are primarily provided by the RBOCs or LECs like Qwest, SBC, and BellSouth, but can also be provided by CLECs like PaeTec, WorldCom, and ACC Business in certain regions.

Local Voice T1s are usually provisioned as digital switched or PRI (ISDN) circuits but in some cases, can be provided as a VOIP solution as in the WorldCom Business Solution product. Digital switched T1s offer customers up to (24) usable channels where PRI T1s generally are configured as
23B+D and allow (23) usable channels with a separate D channel for transmitting data like Caller ID information.

Both of these T1s can be configured to allow traffic overflow, DID/DOD (direct inward dial/direct outward dial) numbers, and customized RTI/TGP (route index/trunk group) configurations.

Depending on the region and providers available, the Local Voice T1s can be provisioned as fully integrated circuits, carrying local voice, switched or dedicated long distance voice, and fractional Dedicated Internet Access.

Point to Point circuits, also known as Private Lines, are circuits that are utilized as connectivity between two locations. Customers can utilize this technology to connect host and remote location or locations in a secure dedicated connection WAN instead of using a service like FRS (Frame Relay Service) or ATM (Asynchronous Transfer Mode).

Point to point circuits can also be used by the customer to connect to a provider's POP for DIA or dedicated voice applications when provisioned through their RBOC or LEC as a "customer provided loop".

This allows the customer to maintain control of their connectivity with the ability to move to a different provider POP if necessary.

Each point to point circuit is distance sensitive, meaning that the price for the circuit will be dependant on the mileage between the two locations that are to be connected. Point to point circuits can be provisioned in full bandwidth allocations ranging from T1/DS1 (1.544Mbps) to OC48 (2488Mbps).

Flat business line (1FB) is plain old telephone service (POTS) providing dial tone and access to nationwide and international carriers. The difference between centrex and a flat business line is that the custom calling feature package is an additional charge and has limited features.

Qwest's retail telecommunication service, Centrex 21, is available for resale by Competitive Local Exchange Carriers (CLECs) to their end-users.

Centrex 21 is a flat rate, business service for customers with 2 to 50 station lines per location. It consists of standard features that are available to all station lines in the shared customer group where available. A Centrex 21 end-user has a choice of having the features delivered via analog lines and/or 2B+S, (digital, voice only) Integrated Services Digital Network (ISDN) lines.

Centrex 21 can be integrated into existing telephone lines, either voice or data, utilizing a choice of different standard and optional features, maximizing productivity. However, the end-users pay for the feature packages regardless of full or partial activation of the features.

Standard Packages, Rate Stability Plans and Optional Features may vary from state to state.Touchtone features are inherent with Centrex 21 and are automatically programmed within the station line.

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 (bearer) channels and a D (delta) channel. The B channels carry 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 user can have up to 128 Kbps service. The Primary Rate consists of 23 B channels and one 64 Kpbs D channel in the United States or 30 B channels and 1 D channel in Europe.