Hoot-n-holler is a type of telecommunications system where you have a permanent open circuit between two or more parties. Anyone can speak at any time over a distance without having to pick up a phone or press a button. It is used, among other places, in stockbroker and warehouse

Warehouse

A warehouse is a commercial building for storage of goods. Warehouses are used by manufacturers, importers, exporters, wholesalers, transport businesses, customs, etc. They are usually large plain buildings in industrial areas of cities and towns. They usually have loading docks to load and unload...

 applications.

Hoot-n-Holler capability provides a business critical and tightly targeted channel of communication which can support thousands of users around the globe and is an integral part of voice trading systems.

Modern Hoot-n-Holler systems are sometimes based on IP Multicast

IP Multicast

IP multicast is a method of sending Internet Protocol datagrams to a group of interested receivers in a single transmission. It is often employed for streaming media applications on the Internet and private networks. The method is the IP-specific version of the general concept of multicast...

. Using IP means old analogue dedicated circuits can be removed and associated cost removed.