A Guaranteed Difference
Voice, data and Internet for Canadian business


Reliable, Cost Effective Digital Voice and Data Connectivity

Solution Building

ISDN PRI plays a key role in many bigger-picture business solutions from Allstream. Here are three you may want to explore:


Allstream’s ISDN PRI service provides full-featured, 2-way connectivity between ISDN compatible PBX or Key Systems and the Public Switched Telephone Network (PSTN).

ISDN (Integrated Services Digital Network) PRI (Primary Rate Interface) offers access to a telecom infrastructure that can dynamically adapt to the changing needs of your business. ISDN PRIs digital nature as well as its ability to dynamically partition itself to accommodate multiple types of incoming and outgoing calls, enables the simultaneous high-speed transmission of both voice and data over a single pipe.

How ISDN PRI Works

ISDN PRI pipes are designed over a standard T1.  They are partitioned into 23B channels and 1D channel.  The D channel acts as the “brain” of the pipe where the B (bearer) channels are responsible for carrying the information payload.  This segregation of D and B channels is known as “Out of Band Signaling” and is the reason for ISDN PRIs versatility.  Other technologies such as Digital Trunk and Business Trunk will have “In-band Signaling” which is not quite as efficient since it reduces the bearer channels delivery to 56kbps and requires line cards for each port. B channels in a PRI can carry 64 kbps of information.  Only one B channel is required to establish a telephone connection. Some data files may be too big to transmit effectively on just 1 B channel; ISDN PRI allows for multiple B channels to be dynamically “bound”, allowing the customer to capitalize on the carrying capacity of the combined channels. When the information has been sent the B channels are automatically “unbound” and made available to other users.

*Conditions apply. Speak with an Allstream rep for details.


Ample Capacity

  • Support for enterprises with large telephony systems (can carry 23 calls on a single line)
  • Supports hundreds or thousands of employees needing to make or receive phone calls (using a relatively small number of PRI lines)

Fully Featured

  • Direct Inward Dialing (DID)
  • Calling Party Numbers (CPN’s) provide Emergency Routing Location (ERL) support for Enhanced 911
  • See full feature set in product details

Better Control

  • You can set and control how the voice traffic flows in and out of your PBX system

Better Quality

  • Because ISDN calls are digital they offer faster connection and tear down times, and clearer signals (i.e. less static) compared to conventional Public Switched Telephone Networks (PSTN).

More Efficient Cost Structure

  • Allstream ISDN PRI enables simultaneous high-speed transmission of voice and data traffic over a single access for activities such as digital (Private Branch Exchange) PBX connections, computer telephony, large file transfers, video conferencing or as backup for dedicated data services. As a result, the number of trunks and interface cards required to deliver lines and consolidate traffic from the PBX can be decreased, reducing costs and IT management hours.

Consolidate and save.
Allstream can help you cost-effectively consolidate voice and data traffic and achieve more efficient integration with the public telephone network.

  • Reduce telecom costs, minimize IT hours and make your overall business operations more cost-efficient.
  • Simplify your network infrastructure, lowering operating and management costs.

Lower your operating and capital costs.
Here are some further ways that Allstream’s Local Exchange Services can save you money:

  • By converging multiple communications channels, you reduce cabling costs.
  • We provide a seamless upgrade path from digital phones to an IP-based system, so you can leave behind the mounting maintenance costs of an aging technology.

Increase your network ROI.
Allstream’s Local Exchange Services are compatible with all commonly used industry-standard equipment, protecting your investment in existing technology. And by integrating voice and data through services such ISDN PRI, you can realize even more value from your telecommunications investment.

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Ample Capacity

Can support 100s or 1,000s of users with a relatively small number of PRIs

Better Quality

Faster connections, clearer signals than conventional business phone lines

Easily Upgraded

When the time is right, provides a seamless migration path to IP-based voice and data services

Solution Building

ISDN PRI plays a key role in many bigger-picture business solutions from Allstream. Here are three you may want to explore:

Applications and Features

Tie Trunks – Create a “link” between two PRI’s that terminate within the same Allstream Central Office switch. Allows 3 or 4 digit internal dialing and name and number transfers.

Release Link Trunking (RLT) – Enables PBX to release lines associated with a recently transferred call. This frees 2B channels on the customers PBX by transferring the work of maintaining a connection to the Allstream switch. The maximum simultaneous calls per PRI is 46. Additional monthly charges apply.

Temporary Local Redirect (TLR) – Redirect incoming calls to alternate locations anywhere in Canada in an emergency situation.*

Virtual Group – A framework within which features such as Call Throttling, Call by Call Routing, etc. is applied.

Hunt Groups – Our three options for moving between Hunt groups are Sequential, Random (most idle) and Circular.

Trunk Groups – All B channels controlled by the same D channel

DID (Direct Inward Dialing) – Enables an outside caller to call an internal extension without having to pass through an operator or attendant first.

Held DID Numbers – Reserve-able a block of DID numbers for future use. This helps ensure consistency within their numbering structure.

Calling Name and Number – For outbound calls, we will carry whatever name the customer’s PBX transmits. If the PRI is an NI-2 PRI, only number can be carried.*

Backup D Channel – Should the original D channel fail, this back up can automatically take over for the other D channel.

Call Throttling – Define the maximum number of calls in or out of a specific trunk group at any given time.

Call By Call Routing – Similar to Inward Route Labelers (IRL) – manages routing of incoming calls based on the TN dialed.

SID (Service Identifier) – A way to further identify a preferred route for a call.

*Some conditions apply. Check with an Allstream representative for details.

Request a quote today
Please enter a valid email

Ample Capacity

Can support 100s or 1,000s of users with a relatively small number of PRIs

Better Quality

Faster connections, clearer signals than conventional business phone lines

Easily Upgraded

When the time is right, provides a seamless migration path to IP-based voice and data services

Our Approach

Count on reliable service and support.
Allstream’s expert technical support and customer service representatives are on call around the clock. As a facilities-based provider, we buy and control our own equipment, so we can:

  • promptly resolve maintenance issues
  • monitor and respond quickly to alarms
  • minimize network downtime
  • deliver dependable service when you need it.

We start with a comprehensive assessment.
In developing any telecom solution, we always look beyond the immediate need, such as replacing an outmoded phone system, to see what else you may want to implement down the road. We can help you take advantage of all that Allstream has to offer, from extended PBX features to sophisticated collaboration tools, over one converged, high-performance all-business network.

We’ve got all the support you need.
From initial project management and installation through long-term technical support and maintenance, Allstream looks after you every step of the way. You can also complement our Local Exchange Services with other solutions from our full suite of Allstream Managed Services, so your IT team can focus even more on supporting the core business.

The Allstream difference: It’s a human quality
Any way you look at Allstream – our customers, our solutions, our network, our track record of innovation, our competitive spirit – we’re truly all business. But that focus demands something very human from us: a commitment to building strong relationships with you, our customers, and delivering value on terms you define.

Our Approach

“They really got involved in the company to understand our challenges. Allstream wanted to be a partner, not just a service vendor.”

Mick Montgomery, Infrastructure Manager Vicwest Inc.

Our IP Network


Our ISDN PRI Services rely on the Allstream IP Network.
Built on rock-solid technology, Allstream’s network offers local telecommunications customers the highest levels of reliability, performance and security. With a self-healing SONET ring technology, our network automatically detects service degradations or failures and reconfigures itself to bypass the problem. Our robust infrastructure enables us to complement your PRI services with customized long-distance and toll-free services that include a whole array of routing, information and planning features.

Gain all the benefits of IP connectivity – nationwide.
Allstream’s high-performance network delivers secure, dependable business communications from coast to coast. Our 30,000 km fibre-optic backbone combines advanced IP connectivity, digital switching, Ethernet-featured services and the latest security technologies. We can help you converge data and video with local, long-distance and private voice traffic over a single network. And we give you global connections through strategic partnerships with leading service providers in more than 70 countries.

Get the best in reliability and security.
Our end-to-end IP infrastructure ensures exceptional quality of service between metropolitan centres across Canada. We deliver critical business applications via highly secure transport modes at gigabit speeds, providing any-to-any connectivity and reliably supporting real-time voice, data and multimedia communications.

Build on our great track record in innovation.
Allstream is an industry leader in emerging areas of IP network convergence and unified communications. For example, we built Canada’s first MPLS virtual private network and IP trunking installations. We can further your organization’s pursuit of innovation on many fronts: to drive ROI on network and IT resources, to reduce infrastructure and operating costs with managed services, and to customize applications that will make your business more agile, efficient and responsive

Our IP Network

The Foundation of our solutions and services portfolio.

  • 30,000 route km across Canada
  • 18,000 route km of inter-city fibre
  • 9 cross-border connections
  • 3,000+ buildings accessed
  • 30 local city networks operations
  • 100 Gig capable DWDM transport
  • International MPLS, Switched Ethernet
    and Wavelength reach

We partner with the world’s best to deliver the best solutions for our customers. For a complete listing of our technology partners, visit the partners section of our website.


“Allstream gets it. They’re a fantastic partner – skilled, experienced and innovative in taking our technology and solutions to the Canadian market.”

Nitin Kawale, President
Cisco Canada