About the role
You will design, deploy and support SIP trunks, hosted PBX platforms and contact-centre telephony for business clients. You will own call routing, quality and security on our telecommunications platform.
What you will do
- Design and deploy hosted PBX and SIP trunking for business clients
- Build call routing, IVRs, queues and ring groups
- Configure and maintain Asterisk, FreeSWITCH or Kamailio servers
- Integrate PBX systems with CRMs, Microsoft Teams Direct Routing and contact-centre tools
- Troubleshoot call quality and signalling with packet captures
- Secure platforms against toll fraud and unauthorised registrations
Minimum qualifications
- Bachelor's degree in Telecommunications, Computer Science or a related field, or equivalent practical experience
- 5+ years engineering SIP and PBX platforms in production
- Expert configuration of Asterisk, FreeSWITCH or Kamailio
- Deployments of 3CX, FreePBX or a similar PBX for business clients
- SIP trunking and interconnects with session border controllers (Ribbon, AudioCodes or Oracle)
- Microsoft Teams Direct Routing configuration
- Linux administration and Bash or Python scripting
- English at CEFR C1 or above (IELTS 7.0 or equivalent)
Expert knowledge
- SIP and SDP in depth: dialogs, transactions, NAT traversal, re-INVITEs and codec negotiation (RFC 3261)
- Media quality: RTP and RTCP, jitter buffers, packet loss, codecs (G.711, G.729, Opus) and MOS
- Platform security: SIP TLS, SRTP, fail2ban, registration limits and toll-fraud controls
- High availability: clustering, failover, load balancing and number portability routing
Preferred qualifications
- 3CX Advanced Certified Engineer
- AudioCodes or Ribbon SBC certification
- Microsoft MS-720 certification (Teams telephony)
- Contact-centre platforms (Genesys, Five9 or similar)
Before any offer we verify your certificates, qualifications, references and right to work in the UK. Security roles also need background screening (BPSS) and may need security clearance.
SOWTK is an equal opportunity employer. We welcome applicants of every background and do not discriminate on any characteristic protected by the Equality Act 2010.