The GXW4500 series are E1/T1 Digital VoIP Gateways that allow digital PSTN and ISDN trunks to be integrated with VoIP networks. By connecting the GXW4500 series with a VoIP network and a traditional PBX or E1/ T1 provider, businesses can drastically increase the amount of PSTN/ISDN trunks integrated with their VoIP network. The GXW4500 series offers three models that provide 1, 2 or 4 E1/T1/J1 spans and support 30, 60 or 120 concurrent calls to cater to the VoIP needs of large and medium sized enterprises. Dual Gigabit autosensing RJ45 network ports with integrated NAT router TLS and SRTP security encryption technology to protect calls and accounts Supports a widerange of voice codecs, including G.722, G.729, iLBC, and more Supports T.38 Fax for creating Faxover-IP Supports multilanguage voice promtps Supports up to 120 concurrent calls