Provide Tier 1 / Tier 2 support for FoIP and SIP-related technical issues via email, phone and case management system (Zendesk)
Diagnose and troubleshoot SIP signaling, call setup failures, one-way audio, jitter, latency, and packet loss
Analyze SIP traces, PCAP captures, and logs using tools like Wireshark and tcpdump
Support T.38 Fax Over IP (FoIP) implementations, troubleshooting failed fax transmissions and improving reliability
Work with PBX systems (Asterisk, FreePBX, 3CX, etc.), VoIP gateways, and SBCs
Assist customers with network configurations, NAT traversal and firewall rules
Escalate complex issues to engineering teams and collaborate with vendors as needed
Take ownership of reported customer issues and see problems through to resolution, ensuring proper recording and closure of all issues
Write documentation, knowledge base articles and FAQs, and document troubleshooting steps, best practices and solutions in the company's knowledge base for use by both internal staff and customers
Test interoperability of new VoIP/FoIP equipment and create user guides for various IP-PBX and SIP-compatible devices for use with our SIP Trunking service.

Bachelor's Degree in Computer Science or related field, or combination of education and experience may be considered
Solid understanding of networking fundamentals (TCP/IP, DNS, DHCP, NAT, VPNs and firewall rules) and networking protocols, in particular VoIP/SIP
Experience with fax and/or FoIP a plus
Experience with Wireshark
Experience with Asterisk, Kamailio, FreeSWITCH, OpenSIPS, or cloud-based VoIP APIs (Twilio, Plivo, Telnyx, etc.)
Working knowledge of Linux/Unix Operating System
Careful, methodical approach to troubleshooting complex technical issues
Experience with help desk ticketing systems (Zendesk, Jira, ServiceNow, etc.)
Excellent written and verbal communications including the ability to explain complex technical concepts to customers
Excellent customer-facing skills.

Technical Support Engineer – SIP, VoIP, FoIP

Key skills