Interruptable Fold Back or IFB is an audio signal that feeds your on-air talent’s earphones so they can hear themselves but can be over-ridden so that the director can speak to them.
Pro Intercom makes a few devices to accomplish this.
The MS301 master station can be configured to use a channel for IFB. You feed the announcers mics from an Aux send on your mixer into the Program Audio input on the MS301 along with possibly the DDR audio from your TriCaster (using the Aux out on the TC). The director can then use one channel on the MS301 to talk to the camera operators and another to talk to the talent.
Alternately you can add a TT-1 and a BP-2 dual channel belt pack for the director. Use the TT-1 to inject the announcers into one channel of intercom. The director can then use the BP-2 beltpack to switch his coms between the announcers and the camera operators. This is a less expensive solution than the MS301 but is not as neat and tidy. You can also substitute a PS301 power supply for the TT-1 to inject program audio into the system.
In all cases you would use TR-1 receivers to feed the announcer’s headphones.
If you are using a TriCaster you can feed the ‘TriCaster’s ‘Internal’ sources to the Aux out. This lets you mix these into the announcers fold back so they can hear clips played in the DDRs etc. You could eliminate the external mixer altogether and just use the Aux out, solo and audio grouping for foldback.
Some moderately confusing diagrams follow.
IFB with a MS301:
IFB with a TT-1: