Contact center technologies, ACD (Automatic Call Distributor), IVR (Interactive Voice Response), speech recognition, text-to-speech (TTS), CTI (Computer Telephony Integration), omnichannel routing, multichannel contact center, call center platforms, CCaaS (Contact Center as a Service), cloud contact center, workforce management (WFM), workforce optimization (WFO), call recording, screen recording, call monitoring, quality management (QM), speech analytics, sentiment analysis, agent desktop, CRM integration, ticketing integration, case management, customer journey orchestration, skills-based routing, queue management, call blending, outbound dialers, predictive dialer, progressive dialer, preview dialer, campaign management, real-time reporting, historical reporting, service levels, ASA (average speed of answer), abandon rate, occupancy rate, adherence, shrinkage, SLA performance, CX (customer experience), omnichannel engagement (voice, chat, email, SMS, social), chatbot integration, AI virtual agents, conversational AI, escalation workflows, callback queuing, voicemail management. VoIP, Voice over IP, SIP, Session Initiation Protocol, SIP trunking, SIP URI, SIP headers, SIP INVITE, SIP REGISTER, SIP OPTIONS, SIP REFER, SIP INFO, SIP re-INVITE, SIP dialog, SIP proxy, SIP registrar, SIP redirect server, SIP user agent (UA), user agent client (UAC), user agent server (UAS), RTP, Real-time Transport Protocol, RTCP, SRTP, media streams, codecs, G.711, G.729, G.722, Opus codec, codec negotiation, transcoding, packetization, jitter buffer, latency, packet loss, MOS score, QoS, DiffServ, DSCP markings, VLAN tagging for voice, voice VLAN, PoE (Power over Ethernet), IP telephony, softphones, IP phones, call sessions, media gateways, voice gateways, PSTN integration, TDM to IP migration, PRI, BRI, E1, T1, CAS signaling, SS7, ISDN signaling, MGCP, H.323, H.248/Megaco.