OpenVox VoxStack GSM Gateways are open source Asterisk®-based GSM VoIP Gateway solutions for SOHOs and SMBs. With friendly GUI and unique modular design, users may easily setup their customized Gateway. Independent System for Each Module Affordable Price with Superior Performance Hot-swap Design for both Sim cards and Modules Compatible with Asterisk®, Elastix®, 3CX, FreeSWITCHTM Sip ServerOverview The modular-designed VoxStack VS-GW1600-series GSM Gateways, ranging from 4 up to 20 GSM channels, developed for interconnecting a wide selection of codecs and signaling protocol, including G.711A, G.711U, G.729, G.722, G.723, G.726, iLBC, GSM & SIP, to the GSM cellular networks to quickly reduce telecommunication expenses and maximize cost-savings. With the unique design of the VoxStack Gateway, it can support hot-swap for both SIM cards and GSM gateway modules. Users can simply add or remove the modules for hardware expansion or exchange. Each GSM gateway module runs an independent Asterisk® system inside. The VoxStack Gateway designs with a Lan Switch board that provides stackability on the hardware upgrade. It supports SMS messages sending and receiving and group sending and SMS to email. The GSM Gateways will be 100% compatible with Asterisk®, Elastix®, trixbox®, 3CX and FreeSWITCHTM Sip Server. Support SMS sending, receiving, grouping sending Support transferring SMS to E-mail Support checking phone number Support SIP1.0/2.0,enhanced SIP function Support USSD service Support IMEI modification Software Platform Linux Features 20 GSM Channels 1 SIM card per GSM channel Quad-Band GSM/GPRS 850/ 900/1800/1900 MHz Fast call setup IMEI and PIN modification 2 LAN ports Applications SOHOs SMEs