Sr Telephony Engineer
Semafone
The Senior Telephony Engineer is a subject‑matter expert responsible for architecting complex telephony integrations, optimizing SBC behavior, guiding customer design decisions, and ensuring Sycurio’s voice platform maintains secure, resilient, PCI‑compliant performance. This engineer leads large customer delivery efforts, resolves advanced SIP/RTP/TLS issues, establishes best practices, and mentors junior team members.
Responsibilities
- Design SIP trunking topologies, call‑routing logic, HA/geo‑redundant configurations, and secure call‑delivery flows.
- Create technical designs that support multi‑tenant and PCI‑compliant call‑processing requirements.
- Engineer DTMF masking flows, encrypted RTP handling, SIP header transparency, and failover paths.
- Validate complex routing requirements involving carriers, CCaaS platforms, and customer IP‑PBXs.
- Lead configuration, tuning, and troubleshooting across SBC platforms (including Oracle and AudioCodes).
- Optimize SIP routing logic, topology hiding, header manipulation, and B2BUA dialog management.
- Diagnose advanced dialog issues involving re‑INVITEs, UPDATE, PRACK/100rel, session refreshes, and media renegotiation.
- Perform deep packet/RTP analysis (jitter, packet loss, SSRC continuity, SRTP negotiation).
- Engage in customer technical workshops, design reviews, and certification testing cycles.
- Own telephony cutovers for complex customer deployments.
- Build standardized templates, automation‑ready configurations, and repeatable design practices.
- Act as top‑tier escalation for SIP/RTP/TLS issues.
- Partner with Cloud/Network Engineering on routing, IP assignments, DNS strategies, and HA design.
- Work with Product & Architecture to shape telephony roadmap improvements.
- Mentor junior engineers and guide operational readiness activities.
- Communicate clearly with customers, translating complex SIP behaviors into understandable guidance.
Architecture & Design
Advanced SBC Expertise
Delivery Leadership
Cross‑Functional & Strategic Contribution
Required Skills
- 5–10+ years in SIP engineering, voice architecture, or SBC‑centric roles.
- Expert understanding of:
- SIP dialogs, message sequencing, timers, PRACK/UPDATE, early media
- RTP/SRTP behavior, codec negotiation, and encrypted media troubleshooting
- TLS/mTLS, certificate validation, SAN/wildcard interactions, cipher negotiation
- Deep SBC configuration experience (AudioCodes, Oracle, or similar major platforms).
- Proven ability to design HA/geo‑redundant SIP environments.
- Extensive SIP trace analysis and packet‑level troubleshooting skills.
- Strong customer‑facing communication and leadership capability.
- Experience producing high‑quality HLDs, LLDs, diagrams, and migration/delivery plans.
- Firm understanding of the TCP/IP stack and Layer 2 and Layer 3 protocols (VLANs, ARP, IPv4, subnetting)
- Firm understanding of enterprise transport technologies (internet, MPLS, VPLS, VPN, P2P circuits) and underlying routing protocols such as BGP
- Firm understanding of hypervisors such as VMware, KVM, and Hyper-V
- Experience in managing SBC and VOIP solutions in AWS Cloud utilizing components such as EC2, VPC, Internet Gateways, and Transit Gateways
- Experience with cloud‑connected telephony paths (public internet, enterprise circuits, cloud connectivity).
- Familiarity with carrier SIP requirements (PAI, trunk groups, routing headers).
- Knowledge of CCaaS ecosystems across multiple vendors.
- Experience with automation/scripting for telephony workflows.
- Exposure to PCI DSS or other regulated environments.
- Experience with Asterisk, RTPengine, Kamailio, freeSwitch VOIP platforms
- Experience QXIP’s HEPIC and/or HOMER.
Nice‑to‑Have Skills
Bonus
Benefits & Culture:
We are a market leader in secure voice transactions and trusted by our customers and partners. We are on a journey to secure all personal data. We recruit diverse, ambitious, innovative people who want to grow in a supportive and collaborative environment. We are passionate, work hard, have fun and celebrate success.
What we'll give you;
15 Days Holiday*
Competitive Salary
Up to 10% Bonus*
4 x Salary Life Insurance
General Health Insurance*
Access to LinkedIn Learning for ongoing professional development
Sycurio is well funded and growing fast, you’ll be joining an organization that combines an entrepreneurial ‘start-up’ culture with the professionalism of a mature and established business. This is a fabulous opportunity to gain experience on a variety of commercial matters of an international business.
*All final interview candidates will be subject to Background check as a pre-condition of a potential offer of employment. Any information found will be considered when making the final hiring decision. Please be aware that the background check process will not go ahead without your written consent.