SII Group delivers Digital Services, IT, Engineering, and Consulting to diverse industries, enabling digital transformation through our commitment to Growth, People, and CSR. With over 16,000 professionals across 21 countries, we’re recognised as a “Great Place to Work” for fostering a high-trust culture. Our core values of Trust, Transparency, and Quality drive our work package delivery, ensuring we meet and exceed client expectations as a committed partner. Since 2016, SII UK has supported top Aerospace & Defence, Aviation, Transportation, and Finance clients, empowering digital transformation with industry-leading engineering expertise. Let’s Tech Together is our promise to encourage innovation and teamwork. We support our engineers with development opportunities and a collaborative, inclusive environment where every voice is valued and empowered. Role We are looking for an experienced Software Engineer with strong C programming expertise to support the development of a mission-critical embedded communication system used in military vehicles. The role involves extending and modifying an existing codebase to improve intercom functionality, integrating IP-based communication features, and ensuring software is delivered to high standards of reliability and compliance. Responsibilities Review and work with the existing baseline software (version 2.0). Implement modifications in C to: Integrate and extend the dismounted call feature. Remove reliance on legacy hardware. Enable automatic call initiation and acceptance using IP and VoIP protocols. Ensure consistent behaviour across multiple crew station types. Update user interfaces (HMI and web configuration pages) to support new functionality. Conduct unit, integration, and regression testing against defined requirements. Participate in structured design reviews (System, Preliminary, Critical, Factory Acceptance). Maintain clear and accurate design documentation, test reports, and review minutes. Collaborate with verification engineers and project teams to ensure compliance. Deliver all source code, compiled load files, and supporting materials securely. Skills Essential Strong C programming background, particularly for embedded systems. Experience with toolchains including: Xilinx ISE, powerpc-eabi-gcc Altera Quartus, nios2-elf-gcc MSP430 CrossWorks (Rowley) TI Code Composer Studio for DSP Proficiency with software development and CI/CD tools: BitBucket, Jira, Bamboo. Experience adhering to strict coding standards and compliance-driven processes. Familiarity with requirements/verification management tools (e.g. Polarion, TestRail). Desirable Background in safety-critical or defence-related software development. Knowledge of VoIP and IP-based communication protocols. Experience contributing to formal design review processes. Benefits Competitive Basic Salary 6% Employers Contribution 6% as a salary sacrifice Private Medical Insurance, Life Cover and Income Protection 25 days holiday 10 days full sick pay per year Flexible working Cycle to Work & TechScheme Continuous professional development Corporate access to the Udemy platform If you're applying for a role requiring security clearance, please be aware that foreign or dual nationality is not an automatic bar, however certain posts may have restrictions which could affect those who do not have sole British nationality or who have personal connections with certain countries outside the UK. http://www.groupe-sii.com/en