The NAT becomes the tough issue when VoIP service provider to deploy the SIP CPE around world. In almost every country, there are many customers are behind the NAT (private IP or virtual IP) or firewall. There is no practical way to handle this problem at the user end. The end users, often do not have network or computer skill. They may also no control of their IP address.

The simple solution SignalSys offered is the server side software, which enables both SIP signaling and media to traverse NAT and firewall without end user involvement.
Products
SP100
SP100X
SP202
SP200X
SP200X-1S1O
SP400
SPV1000
SP100-CL
SP120-PL
USB100
Software
Overview
vmServer -- A simple solution for SIP NAT(Network Address Translation) Traversal.
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SPComm System -- End-to-End VoIP Turn-Key Solution.
SignalSys's SPComm System is a SIP Based softswitch end-to-end total solution for VoIP service provider. It contains Servers and end user devices, such as SP100X, SP200X and etc. The system supports call setup, billing, mass deployment, SIP NAT traversal, and everything needed for VoIP end-to-end service. This solution will help our customers to deploy the VoIP service worldwide rapidly. To service provider, it is a turn-key solution. To end user, it is plug-and-play solution.