Technical Specialist, Fixed Voice

Singapore Telecommunications; Sydney; Hybrid; AUD 180,000 - 240,000; Full time

Benefits offered by this job

Flexible work arrangements

Office on-site amenities

Employee discounts

Parental leave

Job summary

Optus is seeking a Technical Specialist, Fixed Voice to operate and enhance its Fixed Voice network infrastructure across Ribbon platforms. You will handle fault management, complex incident resolution, and proactive KPI monitoring in a hybrid work setup.

The role requires extensive hands-on experience with Ribbon platforms, SIP/TRUNKING, and ITIL processes, plus collaboration with NOC, Engineering and Service Management teams to modernise tooling and observability.

Qualifications

• 15+ years of wireline or Fixed Voice telecommunications experience across Ribbon or GENBAND platforms.
• Deep technical expertise in CS2000 (CS2K), C20 and SBC platforms including call control and trunk management.
• Strong knowledge of Ribbon Fixed Voice architectures including SIP trunking and SIP/TDM interworking.
• Advanced knowledge of SIP, SS7/ISUP, SIGTRAN, TDM E1/PRI, RTP/RTCP, G.711/G.729, DTMF, LNP/ENUM and IPv4/IPv6.
• Experience with Grafana, Kalix/OSIX, Wireshark, Ribbon EMS/RAMP, ServiceNow or similar ITSM tools and Unix/Linux CLI.
• Ability to interpret Fixed Voice KPIs like call completion, ASR, NER and MOS and act on trends.
• Experience in incident management, RCA, maintenance, upgrades, patching, MOP development and vendor TAC engagement.
• Bachelor’s degree in Telecommunications, Electronics, CS or equivalent; Ribbon certifications, CCNA/CCNP Voice and ITIL v4 Foundation preferred.
• Desirable observability, automation and safe AI-assisted operations knowledge.
• Strong ownership and clear communication under pressure with technical and non-technical stakeholders.

Responsibilities

• Operate and maintain Ribbon Fixed Voice nodes (DMS300, CS2000, C20, SBC, PSX, IN and sub-elements).
• Provide Level 2 fault management, incident resolution and technical support for outages and degradations per ITIL.
• Manage escalated faults across Enterprise and Wholesale environments.
• Perform structured fault diagnosis and root-cause analysis with corrective actions.
• Configure and manage C20 elements (GWC, SP2K, G9, MAS, SST, SSL/SESM/A2, CBM, CMT, IEMS, MG15K, NDM).
• Manage SIP trunking, routing and policy rules via Ribbon NMS; SIP/TDM interworking and service validation.
• Investigate voice faults using SIP, INAP, Diameter, RTP and C7/ISUP; use OSIX and Wireshark.
• Execute software upgrades, patch management and planned maintenance with testing, rollback and verification.
• Monitor Fixed Voice KPIs with Grafana and Kalix; address degradation trends affecting call completion, ASR, NER and MOS.
• Develop and maintain MOPs, implementation plans, risk assessments, change records and network docs.
• Collaborate with Network Operations, Engineering, Service Management, NOC, AI Ops, vendors to restore services and improve tooling.

Skills

Ribbon Fixed Voice

SIP/ISUP protocols

Grafana

Wireshark

ITIL incident mgmt

Education

Bachelor in Telecommunications

Ribbon certs

CCNA/CCNP Voice

ITIL v4 Foundation

Tools

Ribbon EMS/RAMP

ServiceNow

Unix/Linux

Kalix/OSIX

Job description

Singapore Telecommunications – Macquarie Park NSW

Optus is an Australian telecommunications company, delivering more than 11 million services to our customers every day across mobile, broadband and digital solutions.

As the Technical Specialist, Fixed Voice, you’ll be accountable for the operation, maintenance, technical support and continual improvement of Optus’ Fixed Voice network infrastructure. You’ll work across Ribbon voice switching and SBC platforms to maintain network availability, performance, resilience and operational compliance, while helping modernise our Network Operations tooling through improved observability, trusted data, OSS integration and automation.

Optus is an Australian telecommunications company, delivering more than 11 million services to our customers every day across mobile, broadband and digital solutions.

As the Technical Specialist, Fixed Voice, you’ll be accountable for the operation, maintenance, technical support and continual improvement of Optus’ Fixed Voice network infrastructure. You’ll work across Ribbon voice switching and SBC platforms to maintain network availability, performance, resilience and operational compliance, while helping modernise our Network Operations tooling through improved observability, trusted data, OSS integration and automation.

What You’ll Do

• Operate and maintain Ribbon Fixed Voice nodes, including DMS300, CS2000 (CS2K), C20, SBC, PSX, IN and associated sub-elements.
• Provide Level 2 fault management, incident resolution and technical support for Fixed Voice platform outages, service degradations and complex operational issues in line with ITIL best practices.
• Manage escalated and complex customer-related faults across Enterprise and Wholesale environments.
• Perform structured fault diagnosis and root-cause analysis, identifying corrective actions and validating the effectiveness of permanent remediation.
• Configure and manage C20 elements, including GWC, SP2K, G9, MAS, SST, SSL/SESM/A2, CBM, CMT, IEMS, MG15K and NDM.
• Manage SIP trunking, routing and policy rules through Ribbon NMS, including SIP/TDM interworking and service validation.
• Investigate voice network faults using SIP, INAP, Diameter, RTP and C7/ISUP protocols, together with OSIX and Wireshark.
• Execute software upgrades, patch management and planned maintenance on Ribbon platforms, including implementation, testing, rollback and post-change verification.
• Monitor Fixed Voice network KPIs using Grafana and Kalix, proactively addressing degradation trends affecting call completion, ASR, NER and MOS.
• Develop, review and maintain Methods of Procedure, implementation plans, risk assessments, technical change records, network documentation and knowledge articles.
• Collaborate with Network Operations, Engineering, Service Management, NOC, Network Enablement & AI Ops, vendors and suppliers to restore services, improve reliability and support the transformation and rationalisation of Network Operations tooling.

What You Bring

• 15+ years of wireline or Fixed Voice telecommunications experience, with hands‑on operational experience across Ribbon or GENBAND platforms.
• Deep technical expertise in CS2000 (CS2K), C20 and SBC platforms, including call control, provisioning, trunk management, signalling configuration and fault resolution.
• Strong operational knowledge of Ribbon Fixed Voice architectures and SBC platforms, including SIP trunking, media policy and SIP/TDM interworking.
• Advanced knowledge of SIP, SS7/ISUP, SIGTRAN, TDM E1/PRI, RTP/RTCP, G.711/G.729, DTMF, LNP/ENUM and IPv4/IPv6.
• Practical experience with Grafana, Kalix/OSIX, Wireshark, Ribbon EMS/RAMP, ServiceNow or equivalent ITSM platforms, and Unix/Linux command‑line tools.
• Ability to interpret Fixed Voice KPIs, including call completion rate, ASR, NER and MOS, and act on emerging degradation trends.
• Proven experience in incident management, root‑cause analysis, planned maintenance, software upgrades, patching, MOP development, change governance and vendor TAC engagement.
• A Bachelor’s degree in Telecommunications, Electronics, Computer Science or equivalent experience. Ribbon certifications, CCNA/CCNP Voice and ITIL v4 Foundation are preferred.
• Knowledge of observability, operational analytics, automation and safe AI-assisted operations is desirable.
• Strong technical ownership, accountability and a disciplined approach to operational risk, with the ability to communicate complex issues clearly to technical and non-technical stakeholders in high‑pressure incident, outage and escalation environments.

The good stuff…

• Competitive remuneration and employee discounts. Make life easier (and more affordable) with $80 monthly credit and 25% off Optus products and unique shopping discounts with our retail partners.
• Flexible working arrangements with opportunities to work three days in the office, two days remote or home.
• Vibrant and collaborative office campus that includes cafes, convenience store, chill out zones, GP, post office, gym and on‑site childcare centre.
• Competitive leave policies, including additional 'Connected’ days to focus on culture, family, health, community, or whatever’s important to you.
• We support growing families with inclusive, carer-neutral paid Parental Leave of up to 16 weeks.
• Build meaningful connections through employee-led networks and diversity initiatives including Culture Connect, Elevate Women, Disability Network and Express Yourself (LGBTQIA+).
• Put your wellbeing first with free access to counselling and support services, 24/7 — in‑person, by phone, SMS, or video.
• Free Optus bus from Macquarie University Metro Station (every 6-8 minutes); morning and afternoon.

At Optus, we are strengthened by others and that means valuing diversity and saying ‘yes’ to embracing individual differences.

We are committed to ensuring that our application process provides an equal employment opportunity to all job seekers, including individuals from diverse gender, cultural and linguistic backgrounds, individuals with a disability, individuals identifying as being part of the LGBTQIA+ community, individuals who may have served in the armed forces or who identify as Aboriginal and/or Torres Strait Islander.

We also want to do our best to make our recruitment process inclusive.

If you require any adjustments or accessibility support to participate fairly and equitably in the recruitment process, please email ***************@optus.com.au or call 1800 309 ***.

https://www.optus.com.au/about/inclusion-diversity For more information on Diversity, Inclusion & Belonging at Optus, please visit https://www.optus.com.au/about/inclusion-diversity