telephony
Asterisk
Asterisk is the open-source telephony engine that VICIdial runs on, handling the actual placing, bridging, and recording of calls beneath the dialer's logic.
Asterisk is the engine that actually moves the calls. VICIdial is the brain that decides who to dial and when, but it does not talk to phone networks itself. It hands those decisions to Asterisk, which places the call, bridges the agent to the lead, plays prompts, and records audio. If you think of VICIdial as the call-center software, Asterisk is the telephone switch sitting underneath it.
Because Asterisk is a full software PBX, it knows how to speak the protocols carriers use — most commonly SIP (Session Initiation Protocol) today. Each leg of a call lives on a Channel, and the rules for what happens to a call as it travels through the system live in the Dialplan. VICIdial generates much of that dialplan for you, which is why most operators never edit it by hand.
The link between the two layers is the Asterisk Manager Interface, or AMI (Asterisk Manager Interface). VICIdial uses AMI to originate calls, transfer them, hang them up, and watch their state in real time. When something in the dialer behaves oddly, the cause is often one layer down — a carrier rejecting a channel, a prompt missing from the dialplan, or AMI dropping its connection. Knowing the split between dialer logic and Asterisk telephony is the first step to reading those problems correctly.
Related terms
AMI (Asterisk Manager Interface)
AMI, the Asterisk Manager Interface, is a control channel that lets software watch live call events and send commands like originate or hangup to Asterisk.
Channel
A single call path on your trunk, where each live call uses exactly one channel, so the channel count is the cap on how many calls can run at once.
Dialplan
The set of rules in Asterisk that decides what happens to each call, matching the dialed number and sending it to the right place step by step.
PBX
A PBX, or private branch exchange, is the phone switch that routes calls inside an organization and connects them out to the public telephone network.
SIP (Session Initiation Protocol)
The standard signaling protocol that sets up, manages, and ends internet phone calls — how VICIdial talks to phones and carriers.