1) For audio communication between the Control Room and Field Operators in process industries. 2) Helps to locate a person in the plant 3) Enables selective conversation between the Control Room & Field Operator 4) Enables selective conversation between the Control Room & a group of Field Operators 5) Enables All Call announcement for all the Field Operators from the Control Room 6) Enables conference among a group of Field Operators & Control Room 7) Enables emergency announcements 8) Enables safety announcement through out the factory 9) Enables paging announcement from any extension of the existing Epabx system 10) The paging announcements are heard through the page speaker connected to each field unit 11) Private conversation is carried on through the handset or through the Private speaker in the field unit 12) Minimum 2 units are required to establish a system . The system finds usage in thermal, fertiliser, chemical, cement,power, steel and other process industries.