Experience : 10+ years About the Project : Were hiring for a strategic engagement with a leading telecommunications client. The role involves contributing to the development and enhancement of a monolithic software image for a custom hardware network device used for peer-to-peer VoIP calling. This device is already deployed in the field with thousands of active users. The engineering efforts include continuous improvement, bug fixes, and new feature development, all delivered to end users through OTA (Over-the-Air) updates. Key Responsibilities : Design, develop, and optimize embedded software running on custom Linux-based network hardware. Enhance and maintain a monolithic software image with a focus on stability and performance for field-deployed units. Diagnose and resolve bugs reported from production devices. Work on integrating and tuning VoIP protocol stacks (SIP, RTP) with FreeSWITCH. Address network-level issues such as latency, jitter, and packet loss for seamless call quality. Implement and optimize audio and signal processing components. Manage build systems and pipelines using Buildroot, Yocto, and Makefiles. Handle OTA upgrade mechanisms and ensure robust update strategies for field devices. Use tools like Wireshark, netmon, and Linux utilities for debugging and performance monitoring. Collaborate with cross-functional engineering teams (hardware, QA, DevOps). Required Skills : Strong programming skills in C/C++ and shell scripting for embedded Linux. Experience with GDB and other debugging tools for embedded systems. Deep understanding of Linux kernel internals, network stack, and device drivers. Experience with FreeSWITCH or similar VoIP media servers. Expertise in SIP, RTP, and network quality troubleshooting (QoS, jitter buffers, NAT traversal). Practical knowledge of signal processing, audio pipelines, and codecs. Build experience with Yocto, Buildroot, Make, and cross-compilation toolchains. Familiarity with OTA delivery systems and upgrade verification processes. Proficient in using Wireshark, tcpdump, netmon, and related network debugging tools. Hands-on with Wi-Fi, Bluetooth, and Linux network manager utilities. Project specific skill : SIP, RTP / SRTP, T.38 and/or G.711 FreeSWITCH / SpanDSP Fluent in C / C++ / C# Understanding of ITU-T compatible soft modems: V.34, V.32bis, V.22bis, V.22 FastConnect, V.21, Bell 103, Bell 212A, V.42, SDLC; Understanding of the Modem-over-IP technology V.150.1; familiarity with the existing solutions (by VOCAL etc) is a plus. RTP, jitter buffer with G.711 voice codec; OS: Linux, Centos. Kernel experience a plus; Device-side development experience is a must have; Wireshark - must be able to interpret PCAP's and to understand and correct communication issues especially for Modem-over-IP applications. The experience in using Git and SW version control; Strong analytical and problem solving skills and self-motivated type that can work independently. Preferred (Bonus) Skills : Contributions to open-source telecom or embedded systems projects. Knowledge of secure OTA update mechanisms, rollback strategies, and signing pipelines. Performance tuning for real-time embedded systems or VoIP gateways. Exposure to containerization (Docker) or CI/CD integration in embedded environments. Education : Bachelor's or Master's in Computer Engineering, Electronics, Embedded Systems, or a related field. Why Join Us : Join a high-impact telecom project with devices already live in production. Work on real-world problems at scale with direct OTA impact on thousands of users. Be part of a collaborative, technically driven environment solving core system challenges. Competitive salary and long-term growth potential with cutting-edge technology. Show more Show less