Elastix NLX-Micro UCS PBX IP VoIP The microUCS is the ideal IP PBX for small business or for your home, allowing you to monitor your communications in a very small but also powerful device that comes pre-installed with Elastix. Technical specifications: Up to 15 extensions (SIP/IAX). Up to 5 concurrent calls. 400MHz CPU / 256Mb RAM / 8GB SD Hard Drive. 1 10/100Mbps Network interface / 1 USB port.