IT and Voice Knowledge for Enterprise
Guides, articles, and technical glossary curated by the SIPPER team from real-world experience designing, deploying, and maintaining enterprise voice, network, and IT infrastructure.
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Cloud PBX, SIP Trunk, Microsoft Teams Direct Routing, VoIP Gateway, Voice AI, and enterprise telephony
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Firewall, SD-WAN, VLAN, WiFi 6/7, network switching, server, storage, and IT infrastructure
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Short definitions for common Voice, Network, and IT terms
Read articlesLatest Articles
What Is Cloud PBX? Complete 2026 Guide
Cloud PBX is a private branch exchange (PBX) phone system that runs on cloud infrastructure instead of on-premise hardware. This guide expla…
Voice & PBXWhat Is SIP Trunk? Complete 2026 Guide
SIP Trunk (Session Initiation Protocol Trunk) is a service that connects your phone system to the public switched telephone network (PSTN) o…
Voice & PBXMicrosoft Teams Direct Routing vs Calling Plans Explained
Organizations using Microsoft Teams have two main options to enable PSTN calling: Direct Routing (connecting in-country SIP Trunks via an SB…
Voice & PBXWhat Is a VoIP Gateway? FXS vs FXO Explained
A VoIP Gateway is a hardware appliance that connects traditional telephony (analog, ISDN, GSM) to an IP voice network (SIP). It lets organiz…
Voice & PBXWhat Is Voice AI in Phone Systems? Transcription, TTS, AI Receptionist
Voice AI in 2026 phone systems is far beyond legacy voicemail. It includes real-time call transcription, automatic summaries, neural TTS for…
GlossaryWhat Is SIP?
SIP is an application-layer protocol for initiating, modifying, and terminating real-time communication sessions like voice, video, and mess…
GlossaryWhat Is PBX?
PBX is the internal telephone switching system in an organization, managing extensions, external trunks, IVR, voicemail, and other telephony…
GlossaryWhat Is IP PBX?
IP PBX is a PBX that communicates over IP networks rather than TDM and copper, primarily using SIP. It enables full VoIP feature sets.…
GlossaryWhat Is Cloud PBX?
Cloud PBX is a phone system that runs on a provider's cloud servers, accessed by customers over the internet on a monthly subscription, with…
GlossaryWhat Is Hosted PBX?
Hosted PBX is a PBX maintained and delivered as a subscription service. Customers do not own the hardware. The term is often used interchang…
GlossaryWhat Is SBC?
An SBC is a border device between two voice networks on IP. It is used to connect customer PBX to carriers, enable Microsoft Teams Direct Ro…
GlossaryWhat Is DID?
DID is a carrier service that gives organizations multiple external numbers, each tied to an internal extension so callers can dial through …
GlossaryWhat Is BYOC?
BYOC lets customers connect their own carrier to Cloud PBX, Microsoft Teams, or UC platforms instead of purchasing voice plans bundled by th…
GlossaryWhat Is G.711?
G.711 is the ITU-T standard audio codec for telephony, using 64 Kbps per direction at 8 KHz narrowband quality. It is the baseline codec sup…
GlossaryWhat Is G.722?
G.722 is an audio codec providing HD voice (16 KHz wideband) at 64 Kbps, same bandwidth as G.711 but noticeably clearer and more natural sou…
GlossaryWhat Is G.729?
G.729 compresses voice down to just 8 Kbps per direction, the lowest of the standard codecs. Ideal for bandwidth-limited WAN links.…
GlossaryWhat Is Opus?
Opus is an open royalty-free audio codec from IETF that adapts bitrate from 6 to 510 Kbps in real time. It outperforms other codecs at any e…
GlossaryWhat Is SRTP?
SRTP is the encrypted version of RTP, used in VoIP to prevent on-path eavesdropping. Pair it with TLS, which encrypts the SIP signaling.…
GlossaryWhat Is VLAN?
VLAN is a Layer 2 segmentation technique that divides one switch into multiple isolated networks, with separate broadcast domains. Used for …
GlossaryWhat Is SD-WAN?
SD-WAN is the modern WAN paradigm: software centrally manages multiple links, selecting the best path per application automatically. It repl…
GlossaryWhat Is QoS?
QoS prioritizes traffic on a network so latency-sensitive apps (voice, video) get bandwidth before tolerant apps (email, file transfer).…
GlossaryWhat Is NAT?
NAT translates IP addresses between private LANs (192.168.x.x, 10.x.x.x) and the public internet. Every office router and firewall uses it s…
GlossaryWhat Is FXS?
An FXS port on a gateway or PBX supplies -48V DC power, dial tone, and ring voltage to analog devices like a carrier line would. Used to con…
GlossaryWhat Is FXO?
An FXO port acts as a phone endpoint, receiving power and ring from a carrier. Used to bring legacy analog trunks from NT or True into an IP…
GlossaryWhat Is DECT?
DECT is a wireless phone standard on dedicated 1.9 GHz spectrum in Thailand. It covers wider area more reliably than WiFi VoIP. Common in fa…