FXS Ports: 4 – FXO Ports: 4- 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