The connection (and aggregation) of phone lines from a PBX to one or more service providers; a variation is SIP trunking which involves connecting a legacy PBX to a VoIP service provider

TelcoBridges and Trunking

TelcoBridges Tmedia and Tdev devices provide trunking capabilities. Multiple different network connections from multiple different service providers (backhaul carriers, international carriers) can terminate in a Tmedia or Tdev device. Call routing can then be applied over top to achieve customer service and operational savings objectives.


Wikipedia article