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EXHIBIT 8.1

SUBSIDIARIES OF CALL-NET ENTERPRISES INC.

|                                   |  |                 |  |                                                              
|---------------------------------- |  | --------------- |  | -------------------------------------------------------------
|                                   |  | Jurisdiction of |  |                                                              
|Subsidiary                         |  | Incorporation   |  | Business Names                                               
|                                   |  |                 |  |                                                              
|Sprint Canada Inc.                 |  | Canada          |  | Sprint Canada
Call-Net Carrier Services
CNCS                 
|                                   |  |                 |  |                                                              
|Call-Net Carrier Services Inc.     |  | Canada          |  | Call-Net Carrier Services
CNCS                               
|                                   |  |                 |  |                                                              
|Call-Net Communications Inc.       |  | Canada          |  | Call-Net Communications,
Communications Call-Net             
|                                   |  |                 |  |                                                              
|Call-Net Technology Services Inc.  |  | Canada          |  | Call-Net Technology
Services, Service de
technologie Call-Net
|                                   |  |                 |  |                                                              
|AlternaCall Inc.                   |  | Canada          |  | AlternaCall, AppelAlterna                                    
|                                   |  |                 |  |                                                              
|CNCS Inc.                          |  | Delaware        |  | CNCS                                                         
|                                   |  |                 |  |                                                              
|Call-Net (Barbados) SRL            |  | Barbados        |  | Call-Net (Barbados)                                          
|                                   |  |                 |  |                                                              
|Call-Net (UK) Limited              |  | United Kingdom  |  | Call-Net (UK)                                                
|                                   |  |                 |  |                                                              
|Time iCR Inc.                      |  | Canada          |  | Time iCR                                                     
|                                   |  |                 |  |                                                              
|Telefirma Canadian Properties Inc. |  | Canada          |  | Telefirma Canadian
Properties                                
|                                   |  |                 |  |                                                              
|ascenda Inc.                       |  | Canada          |  | ascenda                                                      
|                                   |  |                 |  |                                                              
|3989828 Canada Inc.                |  | Canada          |  | 3989828 Canada                                               
|                                   |  |                 |  |                                                              
|4141393 Canada Inc.                |  | Canada          |  | 4141393 Canada                                               
|                                   |  |                 |  |                                                              
|Call-Net Finance 1 Inc.            |  | Canada          |  | Call-Net Finance 1                                           
|                                   |  |                 |  |                                                              
|Call-Net Finance 2 Inc.            |  | Canada          |  | Call-Net Finance 2