By using Portech SBK-32 expander for 32 SIM-cards, you can increase the number of channels in the Portech MV-37X GSM VoIP gateway series using the Internet.
VIET NAM VOIP MARKET PLACE, VOIP PRODUCTS DISTRIBUTOR, IP TELEPHONY SOLUTION AND SERVICE CENTER, SYSTEM INTEGRATION, SOFTWARE DEVELOPMENT, OURSOURCING SERVICE, VIRTUAL OFFICE