Appendix E — Glossary
ACD (Automatic Call Distribution) — A system that routes incoming calls to a group of agents based on rules (round-robin, longest idle, fewest calls, etc.). The Queue feature in this platform is an ACD.
API (Application Programming Interface) — A way for other software to talk to the platform. Used for automation, integrations, and building custom interfaces.
ARPU (Average Revenue Per User) — Total revenue divided by active customer count. A key SaaS metric.
Asterisk — Open-source telephony software that powers the call-handling layer of this platform. You don't interact with Asterisk directly; the dashboard is the interface to it.
BLF (Busy Lamp Field) — A button on a desk phone that lights up to show whether another extension is busy, ringing, or idle.
CCaaS (Contact Center as a Service) — A category of software for running customer support / sales call centers in the cloud. The Queue + Campaign features overlap with CCaaS.
CDR (Call Detail Record) — A log entry for a phone call. Contains caller, callee, duration, billable seconds, hangup cause, and other metadata. Used for billing and reporting.
CNAM (Caller Name) — The name displayed on a recipient's phone when they receive a call. "ACME PLUMBING" instead of just a number. Set per-DID.
Codec — Algorithm for encoding/decoding audio. Common voice codecs: G.711 (high quality, more bandwidth), G.729 (lower bandwidth, slight quality loss), Opus (modern, used by softphones).
DID (Direct Inward Dial) — A phone number that rings into the platform. Bought from carriers, assigned to tenants, routed to extensions/queues/call flows.
DKIM, DMARC, SPF — Email authentication standards. Reduce spam-filter rejections of email sent from your brand domain.
Dialplan — The set of rules Asterisk uses to decide what to do with a call. Generated from your tenant's call flows automatically.
E911 (Enhanced 911) — The emergency number system that requires every phone number to have a registered street address for dispatching responders. Federally mandated.
Extension — A short internal number (e.g., 101, 502) that rings a specific phone or user within a tenant. Each extension has SIP credentials and can be configured for voicemail, FMFM, etc.
FMFM (Find Me, Follow Me) — A feature that rings multiple destinations (extension + cell phone + home phone) when a call comes in, until one is answered.
FOC (Firm Order Commit) — The date a phone-number port is scheduled to actually move from one carrier to another.
HD Voice — Audio quality higher than traditional phone networks (G.722 / Opus codecs). Sounds noticeably clearer.
IVR (Interactive Voice Response) — The "press 1 for sales, press 2 for support" menu callers hear. Built using Call Flows in this platform.
LOA (Letter of Authorization) — A signed document authorizing a carrier to take over a phone number from another carrier. Required for porting.
MOH (Music On Hold) — Audio played to callers waiting in a queue or on hold.
MRR (Monthly Recurring Revenue) — Sum of all your customers' monthly subscription fees. The headline SaaS metric.
MOS (Mean Opinion Score) — A 1-5 rating of voice call quality. Above 4.0 is good.
NAT (Network Address Translation) — A networking concept that affects whether VoIP traffic can flow through a firewall. Misconfigured NAT is the #1 cause of one-way audio.
NPA / NXX — Telephone numbering plan terms. NPA is the area code (501); NXX is the next three digits (555).
PBX (Private Branch Exchange) — A telephone system internal to a company. Cloud-based PBX = this platform.
PJSIP — A SIP stack used inside Asterisk. The newer of two stacks (chan_sip is older, deprecated).
PSAP (Public Safety Answering Point) — A 911 call center. Different jurisdictions have different PSAPs.
Rate Center — A geographic area used for telephone-number routing and pricing. Numbers within the same rate center can usually call each other as a "local" call.
RTP (Real-time Transport Protocol) — The protocol that carries voice audio between endpoints during a call. SIP sets up the call; RTP carries the audio.
SIP (Session Initiation Protocol) — The signaling protocol used for VoIP calls. Sets up, tears down, and modifies calls. Doesn't carry the audio (RTP does that).
SIP Trunk — A virtual connection from a PBX to a phone-number provider (carrier). The platform manages SIP trunks for you.
Softphone — A software application that runs on a computer or phone and acts as a phone (Zoiper, Linphone, native apps). Uses SIP to connect to the platform.
STIR/SHAKEN — A caller-ID authentication framework designed to reduce robocalls. Inbound calls now arrive with an "attestation" indicating how confident the carrier is in the caller ID.
TCPA (Telephone Consumer Protection Act) — US law restricting unsolicited calls/texts. If you do outbound campaigns, you need to comply or face large fines.
Tenant — One of your customer accounts on the platform. Has its own extensions, DIDs, users, voicemail, etc.
Toll-Free Number — Phone numbers in 800/833/844/855/866/877/888 area codes. Free for callers; you pay per inbound minute.
Trunk — Same as SIP Trunk above.
TTS (Text-to-Speech) — Generating an audio file from typed text. Used for voicemail greetings and IVR prompts.
Voicemail-to-Email — Voicemail messages delivered as audio attachments in email, instead of (or in addition to) being available via dial-in.
Wallet — Your prepaid balance with the platform. Funds are drawn down by usage (extensions, DIDs, minutes).
Webhook — An HTTP request the platform sends to your server when something happens (tenant created, call ended, payment failed). Used for real-time integrations.
White-label — Selling our platform under your brand. Your customers see your name and logo, not ours.