Horizon RoutersCost saving making VoLTE calls is extremely simple; just connect the router with your existing analog telephones. Horizon Vision I232-S (4G/LTE VoLTE Wireless Broadband Router) complies with the most popularly adopted VoLTE standard and Circuit Switch protocol to ensure interoperability with SIP devices and major Gateways. This router also supports a wider range of telephony features, such as Call Waiting, Conference, Speed Dial, Return Call, Redial, etc.