This is a read-write text field specifying a Target Carrier Id that, when matched against a call's target carrier ID, causes this peer to be used to hand the call off to that carrier, with the same alphanumeric-plus-hyphen-underscore character restriction. An admin uses this to route outbound calls to a specific downstream carrier interconnect based on carrier identification rather than dialed-number pattern alone. For example, a carrier-interconnect gateway routing traffic to multiple wholesale partners could use this field to ensure calls destined for a particular partner are handed off through the correctly configured peer.