LANCOM 1722 VoIP – LANCOM 1724 VoIP
Chapter 1: Introduction
16
EN
Telephone calls over the PBX and its ISDN telephones remain possible just as
before; the telephones remain available under the familiar telephone num-
bers. This application additionally offers the following options:
In addition to the ISDN telephones, VoIP telephones or VoIP softphones
can be included in the telephone infrastructure. VoIP subscribers in the
internal LAN are also able to call external ISDN subscribers.
The ISDN telephones continue to function, and additionally they can call
all of the internal VoIP telephones and softphones in the LAN.
Calls to external SIP subscribers who use the same Internet provider are
often available at no cost.
With the appropriate connection to a public SIP provider, any other SIP
subscriber worldwide can be called, irrespective of the provider network.
As an alternative to a direct ISDN connection, ISDN network subscribers
can also be reached over a diversion via the SIP provider. The costs depend
on the provider's particular tariff models. Frequently, long-distance and
overseas calls via a SIP provider are significantly cheaper than the tradi-
tional telephone connection.
In this constellation, the LANCOM VoIP Router takes over the switching of the
calls. The device can be individually configured, for example, to use the access
codes to decide upon the switching of a call either via the ISDN interface, or
via the Internet as a VoIP call.
Connecting subsidiaries or home offices to the headquarters
Many subsidiaries or home offices already have a connection to the network
at headquarters over VPN. These connections are normally limited to conven-
tional data transmission. By using VoIP, internal company calls can be made
for free over the existing VPN connection and—thanks to the VPN encryp-
tion—these calls are secured against eavesdropping.
With a LANCOM VoIP Router located in the branch or home office, the two
worlds of traditional and VoIP telephony can be united in a single telephone:
A VoIP telephone or an existing ISDN telephone can be used for free tele-
phone calls via VPN to the headquarters, or to make standard calls via ISDN.
