system
Server trunk
A trunk defined on a specific VICIdial server, telling that box how to hand calls to a carrier so outbound calls can leave by the right path.
A server trunk is a Trunk tied to one specific VICIdial server. A trunk is the road your calls take out to the phone network through a Carrier; making it a server trunk just says which box that road belongs to. On a single-server setup this is mostly bookkeeping, but it becomes important the moment you run more than one server.
Here is the why. Each VICIdial server runs its own Asterisk, and Asterisk only knows about the connections defined on that machine. If you have two servers and one carrier link, each server needs its own server-trunk entry pointing at that carrier, or one box will have no way to place calls. The server trunk is how you record, per box, the path out.
In modern setups the underlying link is almost always a SIP trunk (Session Initiation Protocol trunk), but the server-trunk record sits one level up: it captures the dialing details — what gets stripped or added before the number is sent, which carrier name to use — so the Dialplan knows exactly how to route a call once VICIdial hands it over.
A campaign reaches a server trunk through its Dial prefix — the campaign says which prefix to use, and that prefix steers the call onto the matching server trunk. Get the two in step and calls leave cleanly; get them out of step and you see fast busies or calls that never connect. When you add a server, copying the right server-trunk entries to it is one of the first things to check.
Related terms
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.
Carrier
A carrier is the phone company that actually carries your calls onto the public phone network — VICIdial dials, the carrier delivers.
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.
Dial prefix
A short string VICIdial adds to the front of every number a campaign dials, used to route the call out a specific carrier or trunk.
SIP trunk
A virtual phone line over the internet that connects your dialer to a carrier, letting you place and receive many calls at once without physical wires.
Trunk
The connection between your VICIdial server and your phone carrier that actually carries calls in and out of the system.