Centrex is a business telephone system offered from the local  central office on a subscription basis. It delivers a set of PBX-like features to individual desks with internal and PSTN access for all the features, functions and applications that a business customer needs.

An important benefit of Centrex IP is that it is a leased or rented service, meaning it is fully outsourced.

IP Phone System Service is provided through the  Central Office and the customer does not need to invest in capital equipment or worry about maintenance, power, growth, capacity, and/or changes to configuration.   Centrex Service offers consistent naming, functionality, and standard and optional feature sets across all  markets.  This makes  Centrex ideal for both regional and national customers looking for an outsourced turnkey business telecommunications solution.


When is Centrex Ideal?

Centrex Lines are ideal for small to medium business phone customers who want the sophisticated features and applications of a PBX but want to outsource the care, maintenance and support to their service provider.  Customers will likely have 10 to 99 employees per location with single line telephones and KSU-less telephone equipment or key systems.  Centrex Lines allow these customers to present a sophisticated, bigger-company image to callers by offering the functionality and applications of a more expensive and harder to manage system.

Lower Costs

Unlike PBX or key systems, Centrex requires no large up-front capital expenditure and no investment in redundancy features (with Centrex, unsurpassed reliability is already built into the  switch). In addition to costing less to establish, Centrex is more cost effective in the long term since it doesn’t require a separate maintenance contract and provides rate predictability with multi-year contracts. Since Centrex is fully managed, the customer has virtually no service costs.


Centrex Service offers consistent naming, functionality, and standard and optional feature sets across all  markets.

Linking Multiple Locations

Centrex allows companies with multiple locations in the same city or region to be networked together on one system. This eliminates the need for expensive leased network components to link sites and also makes calls between locations more efficient via abbreviated dialing and more cost effective (calls between Centrex sites are free even where local usage is rated).

Unlimited Growth

It is unlikely that a customer would ever outgrow a Centrex system. The limit on growth is the size of the Central Office, which typically can handle 20,000 to 50,000 lines.

No Switching Equipment

Businesses don’t need to dedicate any room for switching equipment in their valuable office space. Other than the telephone sets, all Centrex equipment is located at the Central Office.

More Efficient Use of Personnel

Centrex does not require in house personnel to manage and maintain the system. In addition, since calls route straight to the desktop, Centrex makes it possible to offload many calls from an attendant who can then take on additional duties.

Improved Customer Service

With Centrex, each person can have his or her own telephone line and DID number which saves callers time, provides more personal service, eliminates caller frustration and improves customer service.

Unsurpassed Reliability

Centrex lets each customer share in features like redundancy, load-sharing circuitry, on-line diagnostics, 24-hour on-premise personnel, mirror image architecture, DC battery backup and UPS (uninterruptible power supply), that are built into the Central Office switch. In fact, the switch is so reliable that customers can expect less than 3.5 hours downtime in 20 years.

Virtually Non-Blocking

All users have simultaneous access to dial tone and PSTN, increasing productivity and reducing downtime.

No Technological Obsolescence

Maintains and upgrades Centrex components and software as new technologies allow. The customer can choose the features and applications that are important to them and pay for only what they need, while they need it.

Standard Centrex Features

These standard features are available to all Centrex customers. In addition, a full array of local and long distance applications are also supported. (for most telecom carriers some restrictions apply)

  • Touchtone
  • Directory Listing
  • 911 Access
  • Caller ID Blocking (per call)
  • Itemized Usage Billing by Extension
  • Station-to-Station Dialing
  • Multiple Appearance of Directory Number (MADN)
  • Executive Busy Override
  • Executive Busy Override Exempt
  • Call Forward Busy
  • Call Forward Don’t Answer
  • Call Forward Variable
  • Call Forwarding of Call Waiting Calls
  • Call Hold
  • Call Waiting Display of Call ID
  • Call Pickup
  • Call Transfer
  • Call Waiting with Cancel Call Waiting
  • Caller ID – Number Only
  • Caller ID per Line Blocking
  • Conference Calling – Meet Me
  • Direct Inward Dial (DID) / Direct Outward Dial (DOD)
  • Directed Call Pickup
  • Business Set Display
  • Hunting
  • Intercept
  • Message Waiting Service (Audible)
  • Message Waiting Service (Visual)
  • Ring Again
  • Speed Calling 8
  • Speed Calling 30
  • Three Way Calling

Optional Features

These features are available to all Centrex customers for an additional monthly charge.

  • Assume Dial “9”
  • Call Park
  • Caller ID Name and Number
  • Automatic Line
  • Remote Access to Call Forwarding
  • Simultaneous Ring (SimRing)
  • Digital Facility Interface (IXC T-1 Access)
  • Automatic Route Selection (ARS) – Basic