Subscriber trunk dialling is the telecommunications framework that automated long-distance routing. It allowed callers to dial a trunk prefix and an area code to connect to exchanges outside their local area. It eliminated the need to book calls through a manual switchboard operator.
Heard on the job
They upgraded the exchange to handle STD, so we can finally dial London direct.
Also heard as
- subscriber trunk dialling
- subscriber toll dialing
Related terms
DDD
Direct distance dialing allows callers to route long-distance calls without an operator.
Subscriber trunk dialling
The automated telephone exchange system that allows callers to dial long-distance numbers directly.
Trunk call
A historic long-distance telephone call routed through major intercity exchanges.