- 2FXS+2FXO ports 2 Giga ETH - 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