NUREMBERG. Funkwerk Enterprise Communications GmbH, a Funkwerk AG company, recently added the VoIP-VPN gateway module to the elmeg ICT systems. This module combines modern Internet telephony by Voice over IP with secure data exchange, together with branch networking over VPN. There are two integrated slots for the M 4 DSP and M 8 DSP expansion modules to upgrade the VoIP-VPN Gateway with digital high compression voice channels for the crossover to the landline network. The new VoIP-VPN gateway is also compatible with older elmeg ICT systems. Thus, this system creates an effective VoIP platform that provides full-range functionality and investment protection at low investment costs to small and medium-sized enterprises.

VoIP-VPN gateway to connect to the Internet

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Mobile employees with a home office can connect directly to their LAN via the Internet using a secure VPN connection to exchange data. And it makes no difference whether they are two or two thousand kilometers away. The telephone and data networks use different protocols and transmission paths, which makes the gateway between the two worlds vitally important. The elmeg VoIP-VPN gateway module supports all the popular network protocols such as ARP, IP, DHCP, DNS PPtP and PPPoE. An elmeg ICT system equipped with the VoIP-VPN gateway can provide all the basic network services, which makes it the ICT communications hub. The system functions as a DHCP server, allocates IP addresses to all the computers in the network, and points to the correct DNS server and Internet gateways. The ICT system also provides Internet access itself. Pre-prepared selection lists of the most common providers makes configuring Internet access very simple. Where access to the Internet is over ISDN, the elmeg ICT system ensures that charges are kept to a minimum by automatically terminating a connection after no data has been transmitted for a configurable period of time. The VoIP-VPN gateway also takes the issue of security very seriously, which is important in this day and age of viruses, worms and operating system vulnerabilities. A Stateful Inspection Firewall blocks unauthorised access from the outside and only permits connections that the administrator explicitly approves using user-defined filters. Pre-configured filters for different client/server applications facilitate this task and ensure that all necessary Internet services are given free access to the web.

Secure Internet telephony with VPN

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SIP has now become an established standard in VoIP for communication between telephones and gateways. The elmeg VoIP-VPN gateway also supports SIP in order to address standard IP telephones in the local network. The VoIP module also permits encrypted speech communication over IP, for example when a branch office of the company is connected to the elmeg ICT system over the Internet, in which case a VPN connection between the locations or directly between the IP telephone and the elmeg ICT system is used. This encrypts the call securely against interception, although the user remains completely unaware of this additional security measure. The elmeg IP-S290 and elmeg IP-S400 system telephones, available from Q 04/2005, can be connected directly to the VoIP-VPN gateway and offer the accustomed system convenience in addition to the standard applications. In order to integrate speech communication into the system at a minimum cost, it is possible to log into any SIP carrier or SIP provider. The most cost-effective supplier is automatically selected by the integration into the LCR (Least Cost Routing) Professional.

DSP modules for the crossover into the landline network

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While a VoIP gateway only permits communication between pure IP telephones, the M 4 DSP and M 8 DSP expansion modules transform the module into a complete landline network to IP gateway. This also makes it possible to transfer IP voice data to the traditional voice network and vice versa. In order to obtain optimum voice quality with the lowest possible bandwidth, the system supports the following common voice codes: G.711, G.723.1, G.726 and G.729a/b. With the combination of an elmeg ICT system, the VoIP-VPN gateway and one or two DSP modules, any traditional terminal device, whether analog or ISDN, and any IP telephone can take advantage of IP voice telephony. Depending on the level of expansion, up to two 8 DSP modules can be added to provide up to 16 simultaneous IP landline network connections.