Callback it's an IVR service used to bridge connection between two external numbers. Callback is triggered by users calling a dedicated number from GSM or PSTN lines. Initiating calls reach a busy signal and then the system calls back the number from which the call was initiated. Next after proper authorization a customer is prompted for a destination number which is provided  by the customer with  DTMF tones. It's kind of a bridge between A and B worth using while total cost of a call to  A and B is lower than when  A calls  B directly - in most cases used for placing international calls.

Callback service requires at least one DID number.

Setup:

• Routing plan - technical prefixes
  Service requires  two dedicated prefixes used by the system to activate selected IVR scenario. It's worth to create prefixes consisted of letters instead of numbers in order to prevent possible conflitcs on routing with calls sent to external gateways. It's also easier to identify the purpose of so-defined prefixes.
   In this manual we will use prefixes:
  cbauth - used in case when a user is recognized by CLI number and does not have to provide  any PIN number.
  The basic scenario for this prefix is "Ask for number"
  cbunauth - used in case when users CLI is not recognized by system and a customer needs to provide a PIN number for authorization.
  The basic scenario for this prefix is "PIN"
  
  A tariff should allow endusers to call these technical prefixes, therefore common part of them "cb" should be added to the tariff with voice rate: 0
  
• Callback routes
  On VSM Routing -> Destinations -> Callback routes should be created new record and configured as below.
  Description: Any name i.e.: Callback
  Dest, leg prefix: cbunauth - the prefix of IVR scenario for clients authorized by  a PIN number
  Authorized client dest. leg prefix: cbauth - the refix of IVR scenario for clients authorized by CLI number
  Triggering delay: time between initiating call and call back to a client
  
  
  Completed setup should be saved with the Create button.
  Depending on needs, the service may work either only for customers recognized by a CLI number (without PIN authorization) or for all - unrecognized clients will be prompted for a PIN number. In order to enable calls to unrecognized users, dedicated Retail account must be created, used by the system to initiate callback calls to their numbers (when initiating CLI is not pointed to any existing account).
  
  All settings of such a system account should enable it to call outbound numbers covered by the service. In case when an initiating user provides correct PIN number, the whole call will be charged to his account. Otherwise, when provided PIN is wrong and a customer fails to authorize, the call between system and the user will be terminated (finished) and charged to the system account created in the previous step.
   Next,  getting back to  Advanced tab of previously created Callback route, there are several options that have to be completed:
  Primary audio codec: codec used by the service - one of codecs supported by termination gateways
  CallBack can be triggered only by users recognized by caller ID: Leaving this option ticked will disable the service from calling back unrecognized numbers - only recognized CLI numbers will be enabled to trigger callback service.
  Unchecking this option will enable the service for any - also unrecognized CLI that will authorize by a PIN number. In case when the option has been unchecked, "user" field should contain mentioned dedicated system account.
  Completed setup form needs to be saved with "Save" button.
  
  
  

• DID number setup
  Dedicated DID number must be pointed to the created callback route on routing plan level.
  Prefix: dedicated DID number
  Route type: callback
  Route: the name of created callback route
  
  
  
  
• After setup is done it's time to test the freshly configured service
  

• Callback it's a service similar to Calling Cards service. All remaining aspects, not mentioned in this manual can be found on Calling Cards. pages.