-FXS Ports: 2- FXO Ports: 0- IMS/SIP/MGCP protocols- Unequalled configurability of FXS and FXO ports- TLS/SRTP- L2TP/OpenVPN client- 500 routing and number-manipulation rules- Configurable SIP ports and IP-address whitelist- High-speed fax with maximum rate of 33 600 bps by T.38 or G.711 pass-through- Polarity-reversal/busy-tone detection- High availability & PSTN failover- Auto provisioning- Remote access via the Redstone Cloud*- Management with the Redstone or third-party Remote Device Management Systems (TR-069 SNMP)- Interoperability with popular SIP servers such as Cisco CallManager/CUCM Broadsoft Microsoft Skype for Business (Lync) and Asterisk/Elastix- Class I lightning protection