1. User guide
   1. 1 Overview
   2. 2 Getting started
      1. 2.1 Connecting
      2. 2.2 A simple overlay
      3. 2.3 Moving an overlay
      4. 2.4 Canceling an overlay
      5. 2.5 Overlaying multiple numbers
      6. 2.6 What next
   3. 3 A more advanced overlay
      1. 3.1 Call announcements
      2. 3.2 Call recordings
      3. 3.3 Advertisers
      4. 3.4 Expiry options
         1. 3.4.1 Setting an expiry
         2. 3.4.2 Enforcing the expiry
         3. 3.4.3 The called extension
      5. 3.5 Restricting calls
         1. 3.5.1 Who can call
         2. 3.5.2 The length of calls
         3. 3.5.3 The number of calls
   4. 4 Advertisers functions
      1. 4.1 Create an advertiser
      2. 4.2 List advertisers
      3. 4.3 Edit an advertiser
   5. 5 Sound file functions
      1. 5.1 Pre-call anouncements
         1. 5.1.1 Create an announcement
         2. 5.1.2 List announcements
         3. 5.1.3 Edit an announcement
         4. 5.1.4 Delete an announcement
      2. 5.2 Call recordings
         1. 5.2.1 Get recordings
   6. 6 Statistical functions
      1. 6.1 Call statistics
         1. 6.1.1 Raw statistics
         2. 6.1.2 Grouped statistics
      2. 6.2 Overlay statistics
         1. 6.2.1 Count your overlays
         2. 6.2.2 List your overlays
      3. 6.3 Real time reporting
   7. 7 Miscellaneous functions
      1. 7.1 Check values
         1. 7.1.1 List number types
         2. 7.1.2 List number classes
         3. 7.1.3 Check a parameter
      2. 7.2 Check settings
         1. 7.2.1 Check your permissions
         2. 7.2.2 Check your settings
         3. 7.2.3 Check call costs
         4. 7.2.4 Check costs for a call
      3. 7.3 Check previous requests
         1. 7.3.1 Count previous requests
         2. 7.3.2 List previous requests
         3. 7.3.3 View request details
   8. 8 Glossary

3.5 Restricting calls

You may not want every overlay to be freely available to every caller. If a user is paying to make a call then you probably don't want anybody else ringing the number. You may also want to restrict how often, or for how long calls can be made to a paticular overlay, the following options allow you to fine tune these details.