Lancom 1723 VOIP User manual

110827/0810
LANCOM Systems GmbH
Adenauerstr. 20/B2
52146 Würselen
Germany
E-Mail: [email protected]
Internet www.lancom.eu
LANCOM 1722 VoIP
LANCOM 1723 VoIP
LANCOM 1724 VoIP
LANCOM 1823 VoIP
LANCOM 1722 VoIP – LANCOM 1723 VoIP LANCOM 1724 VoIP – LANCOM 1823 VoIP
쮿Handbuch
쮿Manual
...connecting your business
110827_HB-LC_1722-1723-1823-17241 1110827_HB-LC_1722-1723-1823-17241 1 11.08.2010 09:09:4311.08.2010 09:09:43

LANCOM 1722 VoIP
LANCOM 1723 VoIP
LANCOM 1724 VoIP
LANCOM 1823 VoIP

© 2010 LANCOM Systems GmbH, Wuerselen (Germany). All rights reserved.
While the information in this manual has been compiled with great care, it may not be deemed an assurance of product
characteristics. LANCOM Systems shall be liable only to the degree specified in the terms of sale and delivery.
The reproduction and distribution of the documentation and software supplied with this product and the use of its contents
is subject to written authorization from LANCOM Systems. We reserve the right to make any alterations that arise as the
result of technical development.
Windows®, Windows 7, Windows Vista™, Windows NT® and Microsoft® are registered trademarks of Microsoft, Corp
Apple, Apple logo, Macintosh, PowerMac, iMac, MacBook, iPhone, Mac OS, Leopard, Snow Leopard, Mac and the Mac
logo are trademarks of Apple Computer, Inc., registered in the U.S. and other countries.
The LANCOM Systems logo, LCOS and the name LANCOM are registered trademarks of LANCOM Systems GmbH. All other
names or descriptions used may be trademarks or registered trademarks of their owners.
Subject to change without notice. No liability for technical errors or omissions.
Products from LANCOM Systems include software developed by the OpenSSL Project for use in the OpenSSL Toolkit (http:/
/www.openssl.org/).
Products from LANCOM Systems include cryptographic software written by Eric Young ([e-mail]).
Products from LANCOM Systems include software developed by the NetBSD Foundation, Inc. and its contributors.
Products from LANCOM Systems contain the LZMA SDK developed by Igor Pavlov.
LANCOM Systems GmbH
Adenauerstr. 20/B2
52146 Wuerselen
Germany
www.lancom.eu
Wuerselen, August 2010
11
082
7/
08
1
0

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Preface
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Preface
Thank you for your confidence in us!
LANCOM VoIP Routers provide the comprehensive functions of an access
router, professional firewall and high-quality VPN gateway and WLAN access
point in a single, compact device. They thus combine investment protection
and cost savings as a reliable voice over IP solution for small and mid-sized
enterprises, home and branch offices.
LANCOM 1823
VoIP only LANCOM Wireless Routers and LANCOM Access Points can be oper-
ated either as self-sufficient Access Points with their own configura-
tion (WLAN modules in "Access Point mode“) or as components in a
WLAN infrastructure, which is controlled from a central
WLAN-Controller ("managed mode"). Please observe the correspond-
ing notices to this in this documentation.
Standard features of the different models are integrated interfaces for ADSL
and ISDN, and a LAN switch. LANCOM 1723 VoIP additionally provides inter-
faces for analog telephone systems. Along with the analog interfaces,
LANCOM 1823 VoIP also provides professional WLAN technology.
In addition to data communications functions, VoIP support transforms
LANCOM Routers into fully fledged, integrated VoIP communications solu-
tions. Along with Quality of Service functions which are optimized for VoIP, the
LANCOM VoIP Routers offer the full range of options required for voice com-
munications over data networks and the step-by-step, cost-effective and sim-
ple migration from existing telecommunications systems to corporate Voice
over IP. The particular characteristics of LANCOM VoIP Routers include, among
others:
PBX functions for analog, ISDN and SIP subscribers
Site connectivity of data and voice via VPN
SIP proxy and registrar for registration with providers and upstream VoIP
PBXs
SIP trunking for multiple parallel lines with extension numbers over a sin-
gle account with a switchboard number.
SIP gateway with transparent transition between SIP and ISDN/analog
telephony
SIP remote gateway provides local SIP, ISDN or analog lines to remote
IP-PBXs.

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Intelligent call routing and number translation
Support of point-to-point and point-to-multipoint connections to the
ISDN network
Multiple configurable ISDN interfaces (NT/TE), some with life-line support
and power relay to the internal ISDN bus
WLAN compliant to the standards IEEE 802.11a/h or IEEE 802.11b/g
Information about your model's functionality in detail is available from the
table 'Just what can your LANCOM VoIP Router do?'.
LANCOM products undergo continuous development. For precise
information about their features and for the latest version of the LCOS
operating system, please visit the LANCOM website.
Model variants
This documentation is to be used for different models:
LANCOM 1722 VoIP
LANCOM 1723 VoIP
LANCOM 1724 VoIP
LANCOM 1823 VoIP
Model restriction The sections of the documentation that refer only to a range of models are
marked either in the corresponding text itself or with appropriate comments
placed beside the text.
In the other parts of the documentation, all described models have been clas-
sified under the general term LANCOM VoIP Router.
Security settings
To maximize the security available from your product, we recommend that you
undertake all of the security settings (e.g. firewall, encryption, access protec-
tion) that were not already activated when you purchased the product. The
LANconfig Wizard 'Security Settings' will help you with this task. Further infor-
mation is also available in the chapter 'Security settings'.
We would additionally like to ask you to refer to our Internet site
www.lancom.eu for the latest information about your product and technical
developments, and also to download our latest software versions.
Components of the documentation
The documentation of your device consists of the following parts:

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Preface
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Installation Guide
User manual
PBX Functions manual
Menu Reference Guide
You are now reading the user manual. It contains all information you need to
put your device into operation. It also contains all of the important technical
specifications.
The PBX Functions manual gives you detailed step-by-step instructions on
commissioning a LANCOM VoIP Router as a PBX (private branch exchange) for
a single location. Also described are the main operating instructions for users,
and how to connect terminal equipment.
The Reference Manual is to be found as an Acrobat document (PDF file) at
www.lancom.eu/download or on the data medium (CD/DVD) supplied. It is
designed as a supplement to the user manual and goes into detail on topics
that apply to a variety of models. These include, for example:
The system design of the operating system LCOS
Configuration
Management
Diagnosis
Security
Routing and WAN functions
Firewall
Quality of Service (QoS)
Virtual Private Networks (VPN)
Virtual Local Networks (VLAN)
Wireless networks (WLAN)
Voice communication in computer networks with Voice over IP (VoIP)
Backup solutions
LANCAPI
Further server services (DHCP, DNS, charge management)
The Menu Reference Guide (also available at www.lancom.eu/download or on
the data medium (CD/DVD) supplied) describes all of the parameters in LCOS,
the operating system used by LANCOM products. This guide is an aid to users
during the configuration of devices by means of WEBconfig or the telnet con-
sole.

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This documentation was created by …
... several members of our staff from a variety of departments in order to
ensure you the best possible support when using your LANCOM product.
Should you find any errors, or if you would like to suggest improvements,
please do not hesitate to send an e-mail directly to:
[email protected]
Our online services www.lancom.eu are available to you around the
clock if you have any questions on the content in this manual, or if you
require any further support. The area 'Support' will help you with
many answers to frequently asked questions (FAQs). Furthermore, the
knowledgebase offers you a large reserve of information. The latest
drivers, firmware, utilities and documentation are constantly available
for download.
In addition, LANCOM Support is available. For telephone numbers
and contact addresses for LANCOM Support, please refer to the
enclosed leaflet or the LANCOM Systems Web site.
Information symbols
Very important instructions. Failure to observe these may result in damage.
Important instruction that should be observed.
Additional information that may be helpful but is not essential.

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Contents
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Contents
1 Introduction 11
1.1 How do ADSL and ADSL 2+ work? 11
1.2 What does VPN offer? 13
1.3 Firewall 14
1.4 Voice over IP 15
1.4.1 Example Applications 15
1.4.2 The central position of the LANCOM VoIP Router 21
1.4.3 VoIP characteristics of the LANCOM VoIP Routers 24
1.5 Just what can your LANCOM do? 25
2 Installation 33
2.1 Package content 33
2.2 System requirements 34
2.2.1 Configuring the LANCOM devices 34
2.2.2 Operating access points in managed mode 34
2.3 Introducing the LANCOM Router 34
2.3.1 Status displays 34
2.3.2 Device connectors 41
2.4 Hardware installation 44
2.5 Configuring the ISDN and analog interfaces 47
2.6 Software installation 47
2.6.1 Starting Software Setup 47
2.6.2 Which software should I install? 49
3 Basic configuration 50
3.1 Details you will need 50
3.1.1 TCP/IP settings 50
3.1.2 Configuration protection 52
3.1.3 Settings for the wireless LAN 52
3.1.4 Charge protection 53
3.2 Instructions for LANconfig 54
3.3 Instructions for WEBconfig 55
3.4 TCP/IP settings for PC workstations 59

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4 Setting up Internet access 61
4.1 The Internet Connection Wizard 63
4.1.1 Instructions for LANconfig 63
4.1.2 Instructions for WEBconfig 64
5 Configuring the VoIP functions 65
6 Connecting two networks 66
6.1 Which details are necessary? 67
6.1.1 General information 67
6.1.2 Settings for the TCP/IP router 69
6.1.3 Settings for NetBIOS routing 70
6.2 Instructions for LANconfig 71
6.3 1-Click-VPN for networks (site-to-site) 72
6.4 Instructions for WEBconfig 73
7 Providing dial-in access 74
7.1 Which details are necessary? 74
7.1.1 General information 75
7.1.2 Settings for TCP/IP 76
7.1.3 Settings for NetBIOS routing 77
7.2 Settings on the dial-in computer 77
7.2.1 Dialing-in via VPN 77
7.2.2 Dialing-in via ISDN 77
7.3 Instructions for LANconfig 78
7.4 1-Click-VPN for LANCOM Advanced VPN Client 78
7.5 Instructions for WEBconfig 80

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8 Advanced wireless LAN configuration 81
8.1 WLAN configuration with the wizards in LANconfig 81
8.2 Point-to-point connections 83
8.2.1 Geometric dimensioning of outdoor wireless network
links 83
8.2.2 Antenna alignment for P2P operations 88
8.2.3 Measuring wireless bridges 90
8.2.4 Activating the point-to-point operation mode 90
8.2.5 Configuration of P2P connections 91
8.2.6 Security for point-to-point connections 94
8.3 Client mode 96
8.3.1 Client settings 96
8.3.2 Set the SSID of the available networks 97
8.3.3 Encryption settings 97
8.3.4 Roaming 98
9 Sending faxes with LANCAPI 101
9.1 Installation of the LANCOM CAPI Faxmodem 102
9.2 Installation of the MS Windows fax service 103
9.3 Sending a fax 104
9.3.1 Send a fax with any given office application 104
9.3.2 Send a fax with the MS Windows fax service 105
10 Options and accessories 106
10.1 Optional AirLancer Extender antennas 106
10.1.1 Antenna diversity 107
10.1.2 Polarization diversity 107
10.1.3 Installing the AirLancer Extender antennas 107
10.2 LANCOM Public Spot Option 108

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11 Security settings 110
11.1 Security in the wireless LAN 110
11.1.1 Encrypted data transfer 110
11.1.2 802.1x / EAP 113
11.1.3 LANCOM Enhanced Passphrase Security 113
11.1.4 Access control by MAC address 114
11.1.5 IPSec over WLAN 114
11.2 Security settings Wizard 114
11.2.1 LANconfig Wizard 115
11.2.2 WEBconfig Wizard 116
11.3 The security checklist 116
12 Configuring the ISDN and analog interfaces in detail 121
12.1 ISDN interface in NT or TE mode 121
12.2 Bus termination, life-line support and power supply 122
12.3 Protocol setting 124
12.4 ISDN connection timing 125
13 Troubleshooting 127
13.1 No DSL connection is established 127
13.2 DSL data transfer is slow 127
13.3 Unwanted connections under Windows XP 128
14 Appendix 129
14.1 Performance data and specifications 129
14.2 Contact assignment 133
14.2.1 ADSL interface 133
14.2.2 ISDN interface ⌧133
14.2.3 ISDN interface 134
14.2.4 ISDN/Analog interface ⌧134
14.2.5 Analog interface 135
14.2.6 Ethernet interface 10/100Base-TX 135
14.2.7 Configuration interface (Outband) 136
14.3 Declaration of conformity 136

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Chapter 1: Introduction
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1Introduction
LANCOM VoIP Routers are fully functional routers with an integrated firewall
to provide local networks with secure access to the Internet.
With the VPN option included, these devices work as powerful Dynamic VPN
gateways for external locations or mobile users.
Along with the ADSL connection, these devices also feature ISDN connections,
and some feature analog telephone connections. An ISDN line can be used to
backup the WAN connection, for remote management of the router, as a basis
for office communications via LANCAPI, and for establishing Dynamic VPN
connections to external locations that use dynamic IP addresses.
By using the Voice over IP function, these devices can transfer voice data over
broadband Internet as well as over ISDN and analog telephone connections.
LANCOM 1823
VoIP only LANCOM Wireless Routers and LANCOM Access Points can be oper-
ated either as self-sufficient access points with their own configura-
tion (WLAN modules in "Access Point mode") or as components in a
WLAN infrastructure, which is controlled from a central WLAN Con-
troller ("managed mode"). Please observe the corresponding notices
in this documentation.
LANCOM VoIP routers can be upgraded with powerful controls over Internet
access with the LANCOM Content Filter Option. This intelligent high-end solu-
tion uses a database-supported web filtering technology that works with pro-
files to control access rights and that also offers practical functions such as
overrides. A system requirement for operating the content filter is LCOS 8.0,
the operating system available for free download from LANCOM.
1.1 How do ADSL and ADSL 2+ work?
ADSL (Asymmetric Digital Subscriber Line) is currently the most common tech-
nology for broadband Internet connections. Standard and almost ubiquitous
telephone lines (analog or DSL) are the basis for DSL data transfer to the near-
est telephone exchange. From here, the data is passed directly on to the Inter-
net over high-speed connections.
The asymmetric DSL variant ADSL was developed for applications where users
receive large amounts of data but transmit only small amounts, such as when
surfing in the WWW. ADSL subscribers can receive data at up to 8 Mbps
("downstream") and transmit at up to 800 kbps ("upstream"). ADSL providers
are able to reduce these maximum rates as they please.

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To satisfy the strongly increasing demand for higher bandwidths, the stand-
ards ADSL 2 and ADSL 2+ provider higher data rates as a basis for applica-
tions such as video streaming or high-definition TV (HDTV) over the Internet.
Depending on the Internet provider, ADSL 2 devices support downstream data
rates of up to 12 Mbps, and ADSL 2+ devices support up to 24 Mbps. Hand-
shake routines during connection establishment ensure that the standards
ADSL, ADSL 2 and ADSL 2+ are intercompatible.
Parallel to data transfer, ADSL also provides full and unlimited support for the
classic applications in telephony (telephone, fax, answering machine, PBX).
This is facilitated by splitters which separate the voice frequencies from the
data frequencies.
The LANCOM VoIP Router features an integrated modem for ADSL/ADSL 2+.
It can be directly connected to the splitter with the supplied cable.
ADSL can operate over both ISDN- and analog telephone lines (POTS – Plain
Old Telephone Service). Devices with an integrated modem are supplied in
two versions. Information about the supported telephone system is to be
found on the type designation on the underside of the device. The device
name is marked on the label along with a suffix which indicates the supported
telephone system:
Annex A-type devices are exclusively to be operated at ADSL-over-POTS con-
nections. Annex B-type devices are exclusively to be operated at
ADSL-over-ISDN connections. Your network operator will be able to inform
Suffix Supported telephone system
'Annex A' ADSL-over-POTS
'Annex A' ADSL-over-ISDN
Splitter
INTERNET
PSTN
Splitter
ADSL Router
ISDN Phone
ISDN
LAN
NTBA

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you of the version you need. These devices cannot be altered or upgraded to
a system other than that for which it is equipped.
There are even ADSL-over-ISDN connections which are not combined with an
ISDN connection, but with a standard analog telephone connection instead.
In Germany, for instance, all T-DSL connections from Deutsche Telekom AG are
implemented as ADSL-over-ISDN connections.
1.2 What does VPN offer?
A VPN (Virtual Private Network) can be used to set up secure data communi-
cations over the Internet.
The following structure results when using the Internet instead of direct con-
nections:
All participants have fixed or dial-up connections to the Internet. Expensive
dedicated lines are no longer needed.
All that is required is the Internet connection of the LAN in the headquar-
ters. Special switching devices or routers for dedicated lines to individual
participants are superfluous.
The subsidiary also has its own connection to the Internet.
The RAS PCs connect to the headquarters LAN via the Internet.
HEADQUARTER
VPN GATEWAY
LAN
SERVER
INTERNET
VPN GATEWAY
BRANCH
LAN
PC
LAPTOP
PC

쐋
Computers using remote access,
e.g. home working

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The Internet is available virtually everywhere and typically has low access
costs. Significant savings can thus be achieved in relation to switched or ded-
icated connections, especially over long distances.
The physical connection no longer exists directly between two participants;
instead, the participants rely on their connection to the Internet. The access
technology used is not relevant in this case: Broadband technology such as
DSL (Digital Subscriber Line) is ideal. A conventional ISDN line can be used,
too.
The technologies of the individual participants do not have to be compatible
to one another, as would be the case for conventional direct connections. A
single Internet access can be used to establish multiple simultaneous logical
connections to a variety of remote sites.
The resulting savings and high flexibility makes the Internet (or any other IP
network) an outstanding backbone for a corporate network.
1.3 Firewall
The integrated stateful-inspection firewall is an effective barrier to unwanted
data traffic as it only permits the entry of data as a response to outgoing data
traffic. The IP masquerading function in the router conceals LAN workstations
accessing the Internet behind a single public IP address. The true identities (IP
addresses) of the individual workstations remain masked. Router firewall fil-
ters allow the blocking of individual IP addresses, protocols and ports. MAC
address filters also offer effective control over the access of LAN workstations
to the IP routing functions in the device.
Further important features in the firewall are:
Intrusion detection
FIREWALL Router
PC
Server
PC
INTERNET

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Attempts to break in to the local network or central firewall are recog-
nized, repelled and recorded by the Intrusion Detection System (IDS) in the
LANCOM. There is a choice of alarms including in-device logging, e-mail
messaging, SNMP traps or SYSLOG alarms.
Denial-of-Service protection
In addition to conventional break-ins, attacks from the Internet may aim
to block the availability of individual services. For this reason, the
LANCOM router is equipped with appropriate security mechanisms to rec-
ognize popular hacker attacks and guarantee router functionality.
Quality of Service/traffic management
The term Quality of Service (QoS) embraces a range of functions in your
LANCOM. QoS functions consider the powerful classification methods
used by firewalls (e.g. restriction to subnets, individual workstations or
certain services). These enable Quality of Service to be very precisely con-
trolled.
By guaranteeing a minimum bandwidth, precedence can be assigned to
enterprise-critical applications, VoIP telephony or certain user groups.
Details about the functions of the LANCOM Router stateful-inspection
firewall are available in the reference manual.
1.4 Voice over IP
The term Voice over IP (VoIP) refers to voice communications over computer
networks based on the Internet protocol (IP). The core idea is to provide the
functions of traditional telephony via cost-effective and wide-spread net-
working structures such as the LAN or Internet. VoIP itself is not a standard,
rather it is a collective term for the various technologies (equipment, proto-
cols, voice encoding, etc.) which make voice communications in IP networks
possible.
1.4.1 Example Applications
Voice over IP solutions offers advantages across a broad spectrum of applica-
tions, starting with small companies and extending to large corporations with
extensive networks of subsidiaries. In the following section, we will demon-
strate a number of examples.
Detailed instructions on configuration are available in the PBX Func-
tions manual or in the LCOS reference manual.

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Operation as a PBX
In many cases, LANCOM VoIP Routers can completely replace a local PBX.
With up to eight voice channels (e.g. LANCOM 1724 VoIP) to landlines, the
possibility to use SIP accounts and SIP trunking, and the data- and voice net-
working of various sites, these are powerful and future-ready alternatives to
conventional PBX systems.
A systematic set of instructions for setting up the LANCOM VoIP Router for this
purpose can be found in the PBX Funtions manual. Beforehand, we recom-
mend that you read the following chapters on the basic setup of devices and
software, and then carry out a basic configuration. You should also have set
up the Internet access before you continue with setting up the PBX functions.
Supplementing existing PBXs
VoIP functions can be conveniently added in to existing telephone structures
by using a LANCOM VoIP Router. The LANCOM VoIP Router is simply con-
nected between the public exchange line (e.g. ISDN NTBA or analog tele-
phone line) and the PBX.
VOIP ROUTER
Analog FAX
PC / Softphone SIP Phone PC / Softphone
INTERNET
SIP SERVER SIP Phone
ISDN
NTBA
ISDN Phone
ISDN
ISDN Phone
ISDN
ISDN Phone
ISDN
Analog Phone
POTS
Example: LANCOM VoIP Router As PBX

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Telephone calls over the PBX and the telephones connected to it remain pos-
sible just as before; the telephones remain available under the familiar tele-
phone numbers. This application additionally offers the following options:
In addition to the ISDN and analog telephones, SIP telephones or SIP soft-
phones can be included in the telephone infrastructure.
SIP subscribers in the internal LAN are also able to call external PSTN
subscribers.
The ISDN and analog telephones continue to function, and addition-
ally they can call all of the internal SIP 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, other SIP sub-
scribers worldwide can be called. As an alternative to a direct telephone
connection, public telephone 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
an SIP provider are significantly cheaper than the traditional 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
VOIP Router
Analog FAX
PC / Softphone SIP Phone
PC / Softphone
INTERNET
SIP Server SIP Phone
ISDN
NTBA
ISDN Phone
ISDN
ISDN Phone
ISDN
PBX
Example: ISDN PBX

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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
encryption —these calls are secured against eavesdropping.
With a LANCOM VoIP Router located in the branch or home office, the two
worlds of traditional (ISDN and analog) and VoIP telephony can be united in
a single telephone: A SIP telephone or an existing analog or ISDN telephone
can be used for free telephone calls via VPN to the headquarters, or to make
standard calls via the conventional telephone network.
The advantages of a telephone connection to headquarters:
The configuration of telephone functions can be carried out centrally in
the VoIP PBX at headquarters.
Subscribers at their branch or home offices connect with the central PBX.
Calls within the company network are free.
Outgoing calls are automatically directed to the optimal line for cost opti-
mization.
VoIP Router
Analog Phone
POTS PSTN
INTERNET
VoIP Router
SIP Phone
PC PC
PC / Softphone
PBX
SIP Phone
SIP PhoneSIP Phone
Branch office Headquarters
Example: Branch office with analog telephone connection, headquarters with SIP-capable PBX

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VoIP for companies through SIP trunking
One of the biggest hurdles for companies that fully migrate to VoIP is to main-
tain the existing telephone numbers. Normal provider SIP accounts come with
a telephone number for the transition to the landline telephone network, but
generally these numbers are selected from a pool of numbers available to the
provider. However, for companies with a large number of telephone subscrib-
ers and numbers, it is of decisive importance that existing telephone and
extension numbers are maintained after migrating to VoIP.
With the SIP trunking function, entire ranges of telephone numbers made up
of external numbers and their associated extensions can be mapped by
LANCOM VoIP Routers over a single connection to a SIP provider, assuming
that the provider also supports Direct Dialing In (DDI) and can provide multi-
ple connections simultaneously. Generally speaking, SIP providers that offer
SIP trunking can acquire the existing telephone numbers from the former tel-
ecomms provider.
Connecting local exchange lines with a remote SIP gateway
Companies with nation-wide and internationally distributed sites are often
interconnected with VPN already. A LANCOM VoIP Router can be used not
only to connect the SIP, ISDN or analog telephones at a branch office to the
SIP-PBX at headquarters; it can also integrate the branch office's local tele-
phone lines into corporate communications with help of the "SIP Remote
Gateway" function.
The SIP remote gateway is active for outgoing and incoming calls.
A company headquarters in New York can, for example, use a LANCOM
VoIP Router with SIP gateway located at the Los Angeles branch office to
telephone with customers and suppliers located in Los Angeles at local
rates ("local break-out").
For improved availability to customers located abroad, the New York
headquarters can, for example, use a LANCOM VoIP Router with SIP
remote gateway located at their sales office in Italy. Customers can then
reach support or service numbers via a standard national telephone
number. Calls over the local exchange line are received and directed
within the company network to the responsible employee. Call routing
can be used which identifies the customer's calling number and automat-
ically selects the appropriate connection to be used for forwarding the
call.