
1) Telephone exchange
Found on
https://www.crosswordclues.com/clue/elastix

Elastix is open source unified communications server software that brings together: The Elastix functionality is based on open source projects including Asterisk, HylaFAX, Openfire and Postfix. Those packages offer the PBX, fax, instant messaging and email functions, respectively. Elastix runs on CentOS operating system and its current stable vers...
Found on
http://en.wikipedia.org/wiki/Elastix

An appliance software that integrates tools available for Asterisk based PBXs into a single interface.
Found on
https://xorcom.com/voip-asterisk-glossary/
No exact match found.