To become a VoIP (Voice over Internet Protocol) engineer, you will need to acquire the following skills and knowledge:

1. Networking: A strong understanding of networking fundamentals is essential for VoIP engineers. You should be familiar with TCP/IP protocols, subnetting, routing, switching, and firewalls. (Perfect!)
2. Voice protocols: Familiarize yourself with voice protocols such as SIP (Session Initiation Protocol), RTP (Real-time Transport Protocol), and H.323. You should have a good understanding of how these protocols work and their significance in VoIP systems. (H.323 is kind of obsolete in my opinion)
3. VoIP hardware: Understand the hardware components that make up a VoIP system, such as IP phones, gateways, and switches. (Correct!)
4. Quality of Service (QoS): QoS is crucial in VoIP systems to ensure that voice traffic is given priority over other types of traffic. Learn about QoS techniques such as traffic shaping, traffic policing, and packet prioritization. (Lately with high speed networks, QoS is having less and less importance in my modest opinion)
5. Troubleshooting: Being able to diagnose and resolve issues in a VoIP system is critical. You should be familiar with common VoIP problems such as call drops, jitter, latency, and echo, and know how to troubleshoot them. (For sure)
6. Security: VoIP systems can be vulnerable to attacks, so it is important to understand how to secure them. Familiarize yourself with techniques such as encryption, access control, and network segmentation. (Correct)
7. Programming: Programming knowledge may be useful for customizing or creating VoIP applications and services. (Correct)

If you are interested in becoming a VoIP engineer specifically focused on open-source voice technologies, you will need to acquire additional skills and knowledge in the following areas:

1. Open-source VoIP software: Familiarize yourself with popular open-source VoIP software such as Asterisk, FreeSWITCH, Kamailio, and OpenSIPS. Understand how to install, configure, and customize these platforms. (Perfect!)
2. Linux operating system: Most open-source VoIP software runs on Linux, so a good understanding of Linux operating system is necessary. Familiarize yourself with commands, file systems, and security. (Good)
3. Scripting languages: Open-source VoIP software often requires scripting to customize or automate tasks. Familiarize yourself with scripting languages such as Python, Perl, and Bash. (Correct!)
4. Database management: Many open-source VoIP software solutions require the use of databases to store configuration data and call records. Familiarize yourself with database management systems such as MySQL, PostgreSQL, and SQLite. (Very important, more than 35% of the time spent in tech support is related to databases and CDR handling at our company SipPulse)
5. Virtualization: Open-source VoIP software can be deployed on virtualized environments. Familiarize yourself with virtualization technologies such as VMware, VirtualBox, and KVM. (All VoIP engineers will do a lot of these, plus cloud, AWS, Azure, Oracle…)
6. Web technologies: Open-source VoIP software can be integrated with web applications. Familiarize yourself with web technologies such as HTML, CSS, JavaScript, and REST APIs. (Maybe, REST APIs are important).

You can acquire the necessary skills and knowledge by taking courses, attending workshops, and gaining hands-on experience by contributing to open-source projects, participating in online communities, and setting up your own VoIP systems using open-source software. Additionally, you can obtain industry certifications such as the Digium Certified Asterisk Administrator (dCAA) and the FreeSWITCH Certified Professional (FSCPTM) to validate your skills and knowledge in open-source VoIP technologies. (Here it is funny, The FSCPTM does not exist, sometimes GPT guess responses, how he got on this?)