The Alcatel 1000 S12 is a highly scalable and modular digital switching system that has played a significant role in global telecommunications infrastructure for decades. Known for its reliability and adaptability, the S12 has been deployed extensively across both urban and rural networks. At its peak, over 140 million Alcatel S12 subscriber lines were active in more than 100 countries, highlighting its worldwide acceptance and long-term performance.
Originally developed to support a wide range of services—including voice, data, and ISDN—the S12 system continues to be a critical component in many networks, particularly where long-term stability and proven performance are essential. Its modular architecture allows for flexible configurations and easy integration with both legacy and modern network elements, making it a valuable asset even in evolving telecom environments.
Carritech is proud to offer a full range of support services for the Alcatel 1000 S12. Our capabilities include:
Repair and refurbishment of S12 modules and components, helping to extend the operational life of your equipment.
Comprehensive parts supply, with thousands of components available from stock or through our trusted global network.
Technical support and consultancy provided by engineers with deep expertise in Alcatel systems, ensuring that your network remains reliable and well-maintained.
Spares management and lifecycle extension planning, enabling you to effectively manage existing infrastructure and plan future upgrades.
With years of experience working on Alcatel technologies, Carritech is well-positioned to help you maintain your 1000 S12 systems efficiently and cost-effectively. Whether you’re looking to prolong the life of your legacy infrastructure or require assistance with specific modules or configurations, we are here to support you every step of the way.
The Alcatel 1000 S12 switching system (formerly known as ‘System 12’ or ITT 1240) is also one of the most popular in the world including at one point in time 140 million Alcatel S12 lines in more than 100 countries worldwide.
The Alcatel S12 is an optimized cost-effective, multi-purpose voice switch covering the entire exchange application range of local, toll, combined local & toll, tandem and international exchanges.
The Alcatel S12 Media Gateway Controller(MGC) was later designed to meet the Next generation network (NGN) requirements and employing this product together with the Alcatel 7510 Media Gateway (MG), service providers can handle both TDM and voice over packet (VoP) traffic in an NGN architecture.
The Alcatel S12 is capable of the following capacity:
The S12 can be used for a huge range of switching applications: Remote subscriber units, small, medium and large local exchanges, tandem, toll and international exchanges, operator assistance systems, network service centres, telephone traffic charging centres, mobile switching centres, service switching points and signalling transfer points.
The Alcatel 1000 S12 is capable of providing services such as telephony, bearer services, tele-services, supplementary services, file transfer, transmission of video and images, and LAN interconnection.
The Alcatel 1000 S12’s software functions are distributed over the processors which control the exchange.
The S12 software has five major sub-systems: operating system, telephonic support, call handling, maintenance and administration.
The Alcatel S12 system’s distributed control architecture incorporates modular hardware components which conform to a defined interface with the DSN (Digital Switching Network).
The modular design means that the exchange architecture, and top-level software don’t need to be adapted when updating smaller features such as components, microprocessors or custom VSLI circuits.
The number of different printed circuit board types is only 29 for a typical exchange. The number of different rack types from which a typical exchange is built is 4. For a typical 10,000 line exchange the Alcatel 1000 S12 has 9 racks and 9KW of power.
The Alcatel 1000 S12 ISDN Remote Subscriber Unit (IRSU) is suited to serve remote concentrations of subscribers and to shorten the loop length in urban areas. It is a mixed analog/ISDN telephone line concentrator which provides access to an Alcatel 1000 S12 exchange.
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From expert maintenance and repair to reliable part sourcing and technical consultation, we provide comprehensive support for every stage of your network’s lifecycle. Whether you’re extending the life of legacy systems or integrating with modern infrastructure, our team ensures seamless, efficient, and cost-effective solutions—so you can focus on performance, not problems.
Understand how this switching system integrates into both legacy and evolving telecom networks, its common applications, and how we support it with expert repair, maintenance, and spare parts services. Whether you’re running an active S12 system or navigating a transition phase, you’ll find all the essential information and support you need right here.
