Call for price: Yes
Public Price (MSRP): Varies
Manufacturer: Aastra
Availability: New, Refurbished
H/W Warranty: 1 year
Protocol: Analogue (SLT)


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's premises, 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 (unit number).

Centrex obviates the need for separate exchange lines delivered to a site for use with a 1A2 Key System or similar, or PBX. 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, in an arrangement called "key behind 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 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 had their own network of private lines crossing the country or to distant countries. Managing these networks of "Tie Lines" and connecting users to them was also an important part of Centrex.


At Nine-One-One we have a wide selection of Centrex telephone sets available in different colours, as well as new and refurbished conditions.

  • The M5208 is MADN-capable, letting you program your set for appearances of other users' directory numbers. Call coverage is simple.
  • The 2-line X 24-character liquid crystal display can tell you who is calling and whether the call was transferred or forwarded. Armed with such information, you can answer personally and appropriately.
  • Visual ringing indication alerts you to an incoming call with a flashing lamp. Even if you are on your primary line, you won't miss important calls.
  • The M5208 includes eight programmable line/feature keys as well as conveniently placed, color-coded Hold and Release keys for improved efficiency and better call processing.
  • The built-in speaker permits on-hook dialing and makes it easy to access voice mail.
  • The M5208 is loop powered. Because local power is not required, your set will retain display capabilities even during a power outage.
  • The M5216 is headset compatible.
  • The 2-line X 24-character liquid crystal display can deliver call information such as call progress, queue status, and calling name and number. Agents or the attendant can use this data to greet callers and speed transactions.
  • Fourteen programmable line/feature keys let you tailor the set to fit your requirements. Assign additional directory numbers or special ACD features used by your organization.
  • The M5216 supports a maximum of two M522 Meridian Mate expansion units to let you expand your answering position in a modular fashion.
  • The M522 Meridian Mate Expansion Module is compatible with both the M5216 and M5316. The M522 is a 22-button expansion unit, with associated LCD indicators, providing additional keys for lines or features.
  • Up to two expansions can be used, for a total of 44 extra programmable buttons. Combined with Meridian Digital Centrex, the M522 offers effective mini-console capabilities.
  • Handsfree operation permits you to engage in a conference call while simultaneously performing other tasks. During the conference call, use the Mute key to confer confidentially with another person in the room.
  • Thirteen programmable line/feature keys let you tailor your set to suit your needs. The Program key lets you further customize local features on your set, such as time and date.
  • The M5316 gives you one-button access to the MDC features you use most, including Speed Call. The built-in Call Timer makes it easy to monitor calls. And the Speaker allows convenient on-hook dialing and access to voice mail.
  • The 2-line x 24-character liquid crystal display ensures easy access to call information, including date and time.


If your existing Centrex service is being discontinued, we would ask you to please consider the ERICSSON-LG iPECS products such as; the iPECS eMG80, iPECS eMG800 or if you are looking for a pure IP solution, the iPECS UCP. Feel free to contact us via the Sales Enquiry page, and we'll gladly put you in contact with one of our local dealers.


For more information or quotes on anything you see on our website, please feel free to contact our Sales Department, CHAT or call on +1 (403) 252-0911 and we'll be more than happy to help you with all your communications needs.

Staff at Nine-One-One Communication Supply


© 2019 Nine-One-One Communication Supply Inc.