SIM Services

SIM services consist of new generation network management solutions (SoftSwitch and multiSWITCH) and SIM servers and controllers.

Topex multiSWITCH and SIM servers are located in the centre of the Next Generation Networks architecture. The carrier-grade softswitch solution provides call-control, multiple services and multiple types of signalling. It features Class 4 and Class 5 telecom services over an IP-based infrastructure managing traffic and routing to users on a mobile network.

Operators will find the following benefits:

  • Centralized operation of all SIM cards
  • Each SIM box can accommodate up to 512 SIM cards
  • Flexible and dynamic allocation of any SIM to any gateway at any time
  • No remote - local SIM cards need to be installed
  • Flexible SIM timing settings (selectable algorithms, time of day or per minutes usage)
  • Group based SIM card management on the SIM-Server
  • Cost optimiser - according to tariff schemes & price plans of the network operators
  • No neefd to visit remote site for card replacement, managed centrally
  • Charging of pre- paid SIM cards is performed remotely, from the web interface of the SIM server
  • Programmable dynamic allocation of any SIM to any GSM channel of any gateway, anytime
  • Generates detailed log files. These files can be sent out by mail
  • Warnings and error messages (e.g. blocked SIMs) may be sent by e mail or SMS


The Topex SIM Server system consists of:

  • One or several SIM boxes, each with several SIM boards
  • A central SIM Server, that manages all the SIM boxes and Gateways
  • Remote Gateways

Principles of operations:

  • All SIM cards are physically stored in SIM boxes located where most convenient, usually centrally for ease of management
  • The SIM Server allocates the SIM card remotely, via an IP address
  • The GSM modem has access to the remote SIM via a GSM terminal adapter/SIM emulation.

Features of SIM server:

SIM server is based on a Linux pc with:

  • SIM card management via IP from one central location
  • SIM server database.
  • Advanced least cost routing (LCR) functions
  • Management software and remote administration console TCP/IP

Features of SIM Box:

  • 19 inch rack, 6U height
  • Compact PCI back plane with one CPU slot and up to 16 slots or smart card board
  • Supports hot swapping for smart card boards
  • Power Supply: 230V/110VAC @ 47- 67Hz

This compact PCI equipment supports up to 16 smart card boards, and each board has holders for 32 SIM cards, thus a total of 512 SIM cards.

To ensure continuous operation, it is highly recommended uninterruptible supplies, (UPS) is used, for powering the SIM Box and the SIM server.


Each mobile module has attached a SIM emulator (hardware + software). This way every GSM channel can be dynamically configured to use the best available tariff, at any moment of time.



C21 Communications provides solutions and products designed to reduce the cost of telephony for SoHo and SME businesses, right through to global enterprises.

C21 Communications Ltd. Harwell International Business Centre, 173 Curie Avenue, Harwell, Didcot, Oxfordshire, OX11 0QG.


Contact Number: +44 1235 838592