Available in the Field Engineer marketplace are experts with Voice over Internet Protocol (VoIP) skills, which is a mix of voice, video, and knowledge on one network. VoIP allows people to make telephone calls over broadband Internet connections rather than analog landlines. A VoIP engineer designs, tests, installs and maintains both local VoIP systems in business and large networks that cover entire regions.

VoIP Engineers use their experience with computer science, digital audio hardware, and VoIP software to install cutting-edge technologies. They also work with information technology (IT) professionals and system administrators to explain the functionality of VoIP. Many industries employ VoIP engineers to complete telecommunications work on a full-time or contract basis.
Experienced VoIP engineers develop programs that convert speech and audible sounds into digital signals called codecs. These codecs condense audio into data packets and send these packets through an IP network to translate the packets back into sound at the other end of the connection.

VoIP endpoints use international telecommunication union (ITU) standard codecs viz. G.711 (standard for transmitting uncompressed packets) or G.729 (for compressed packets). ITU-T.38 is used for sending faxes over VoIP or an IP network in real time.