Telecommunication Solutions
Impossible Just Takes Longer to Design

Call Back

Service requests

Subscribers can order the call back service by sending an SMS or USSD message to a service number. Call Back requests can also be made by email or through a website.


PROTEI Call Back can make repeated attempts to call the requested number if there is no answer. The number of redial attempts can easily be set by the operator.

System administration

Administration is carried out using a multifunctional web interface.

Operational logs

The Call Back server can store information about status, start and end times of conversations, source and destination numbers. Call Back can save this information internally as well as in an external database.


  • MSC connection via E1 trunks (SS7/ISUP or PRI protocols) – up to 4 E1 per module
  • SMS/USSDC connection using SMPP v3.4 protocol over TCP/IP (Ethernet 10/100 Base-T)
  • Order receipt from SMS, USSD or voice calls
  • VLR blacklist support to restrict USSD access to the service from selected networks
  • Request originator IMSI or MSISDN can be accepted in USSD request
  • ODBC/XML interface to external databases for IMSI-to-MSISDN conversion
  • Number modification
  • SMS message to inform the calling party if the called party cannot be reached
  • Open API for integration with third-party prepaid platform
  • Remote service configuration
  • Alarm and event logging

Administration and Maintenance

  • Flexible SS7 configuration
  • Mail client management
  • Management of SMPP connections to SMSC for receiving orders and sending messages (IP address, port, address information)
  • VLR blacklist configuration
  • SMS and USSD message text management