How do I find out which features an extension is permitted in COS (Class of Service) on MN3300 system?

If certain features are not available, or do not work on an extension, it could be barred through its Class of Service (COS).

What an extension is allowed to do:  

  • Find the particular extension's Class of Service number in the Station Service Assignment form.
  • Find out what is allowed for that COS number in the Class of Service Options Assignment form.

In detail:

  1. Log into the MN3300 with a login id and password
  2. Click on System Administration Tool
  3. Select System Options
  4. Select the Station Service Assignment form
  5. Find the COS number for the extension in question. eg 2
  6. Select the Class of Service Options Assignment form
  7. Highlight the COS number (eg 2) in question
  8. In order to see what is permitted, click on the blue change button on the right hand side of the screen

Alternatively Access the Station Service Assignment and Class of Service assignment forms by:

  1. Logging into the MN3300 with a login id and password
  2. Clicking on System Administration Tool
  3. Select All Forms (alphabetical)
  4. Find the necessary forms from the alphabetical list


  • Making any change in the COS Options Assignment form will affect every extension that has that particular COS number.
  • If making no changes in the COS Options Assignment click on the blue cancel key.
  • Allow and barring for outgoing calls are executed through Class of Restriction (COR) forms.