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.
We specialize in
Fax Store-and-Forward
and Fax Broadcast,
Real competitive
low-cost International Calling,
Callback and Call-through,
Conferencing
as well as
VoIP Phone Services
and Voice Wholesale