ELTEX TAU-8N.IP User manual

VoIP Gateway
TAU-8N.IP
User Manual
Firmware version 1.4.0
MGMT IP address: 192.168.1.1
Username: admin
Password: password

TAU-8N.IP User Manual. Version 1.4.0.
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Contents
INTRODUCTION..................................................................................................................................................................... 5
1. PRODUCT DESCRIPTION................................................................................................................................................ 6
1.1. Purpose ................................................................................................................................................................. 6
1.2. Device Specification.............................................................................................................................................. 6
1.3. Device Design and Operating Principle................................................................................................................. 7
1.4. Main Specifications............................................................................................................................................... 9
1.5. Design ................................................................................................................................................................. 11
1.6. Light Indication .................................................................................................................................................... 13
1.7. Reset to Factory Settings .................................................................................................................................... 14
1.8. Delivery Package................................................................................................................................................. 14
2. DEVICE MANAGEMENT VIA WEB CONFIGURATOR .................................................................................................... 15
2.1. Getting Started .................................................................................................................................................... 15
2.2. User Change........................................................................................................................................................ 16
2.3. Web Interface Operation Modes ......................................................................................................................... 16
2.4. Applying and Discarding Changes Made to Configuration ................................................................................. 17
2.5. Quick Configuration Menu.................................................................................................................................. 18
2.6. Advanced Settings............................................................................................................................................... 21
2.7. System Monitoring.............................................................................................................................................. 78
2.8. Example of device configuration ........................................................................................................................ 88
3. SUPPLEMENTARY SERVICE USAGE.............................................................................................................................. 90
3.1. Call Transfer ........................................................................................................................................................ 90
3.2. Call Waiting.......................................................................................................................................................... 92
3.3. Three-party Conference....................................................................................................................................... 93
4. CONNECTION ESTABLISHMENT ALGORITHMS ........................................................................................................... 95
4.1. Algorithm of a Successful Call via SIP Protocol................................................................................................... 95
4.2. Call Algorithm Involving SIP Proxy Server........................................................................................................... 96
4.3. Call Algorithm Involving Forwarding Server ....................................................................................................... 97
4.4. DHCP-based Autoprovisioning Algorithm........................................................................................................... 98
5. SYSTEM RECOVERY AFTER A FIRMWARE UPDATE FAILURE ..................................................................................... 102
6. APPENDIX A. CALCULATION OF PHONE LINE LENGTH.............................................................................................. 103
7. APPENDIX B. RUNNING USER-DEFINED SCRIPT UPON SYSTEM STARTUP................................................................ 104
8. APPENDIX C. DHCP CLIENTS CONFIGURATION IN MULTISERVICE MODE ................................................................ 105

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Document version Issue date Revisions
Version 4.0 28 April 2023 Fourth issue
Version 3.0 30 September 2022 Third issue
Version 2.0 10 June 2022 Second issue
Version 1.0 18 December 2020 First issue
Firmware version Firmware version 1.4.0
EXPLANATION OF THE SYMBOLS USED
Symbol Description
Bold font face Notes, warnings, section headings, titles and table titles are written in bold.
Calibri Italic Important information is written in Calibri Italic.
NOTES AND WARNINGS
Notes contain important information and recommendations on device operation and setup.
Warnings inform users about hazardous conditions, which may cause injuries or device damage
and may lead to the device malfunctioning or data loss.

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INTRODUCTION
Today, VoIP is one of the most rapidly evolving telecommunication services. TAU-8N.IP series gateways
(hereinafter the "device") are designed to provide VoIP services to the network clients.
TAU-8N.IP VoIP gateway allows connecting analogue phones to packet-based data networks accessible via
Ethernet. The device is intended for operation in home or small offices (SMB).
This operation manual describes intended use, key specifications, configuration, monitoring, and firmware
update for TAU-8N.IP VoIP gateways.

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1. PRODUCT DESCRIPTION
1.1. Purpose
TAU-8N.IP is a high-performance VoIP gateway with the full set of features that allow users to take advantage
of VoIP functionality. TAU-8N.IP gateway allows connecting an analogue phone or a fax modem to IP
networks.
The devices and connection wires for subscriber device connection are specified for unmanned
day-and-night service in the close heated spaces with ambient temperature from +5 to +40 °С and relative
humidity from 20 % to 80 %. The device does not include built in voltage and current protection for subscriber
terminations.
1.2. Device Specification
Interfaces:
• FXS: 8 × RJ-11 ports;
• WAN: 1 × RJ-45 10/100BASE-T Ethernet port;
• MGMT: 1 × RJ-45 10/100BASE-T Ethernet port;
• USB: 1 × USB 2.0 port.
The gateway is powered by external 12 V DC adapter for 220 V electrical networks.
Functions:
• network functions:
• PPPoE support (PAP/SPAP- and CHAP/MSCHAP-V2-authorization, PPPoE-compression);
• L2TP support;
• static address and DHCP support;
• network screen;
• NTP support.
• VoIP protocols: SIP;
• echo cancellation (G.168 recommendations);
• voice activity detection (VAD);
• comfort noise generation;
• DTMF signals detection and generation;
• DTMF transmission (INBAND, rfc2833, SIP INFO);
• fax transmission:
• G.711A/G.711U;
• T.38.
• operation w/ and w/o a SIP server;
• Supplementary Services:
• Call Hold;
• Call Transfer;
• Call Waiting;
• Call Forward on Busy;
• Call Forward on No Answer;
• Call Forward Unconditional;
• DND (Do Not Disturb);
• Caller ID: FSK, DTMF;
• Hotline;
• Group call;
• Call Pickup;
• Three-party Conference;
• Flexible dialplan.

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• firmware update via web interface;
• DHCP-based auto provisioning support;
• TR-069;
• remote monitoring, configuration and setup: web interface, Telnet, SSH.
Figure 1 shows TAU-8N.IP connection diagram.
Figure 1 — TAU-8N.IP connection diagram
1.3. Device Design and Operating Principle
TAU-8N.IP terminal includes the following subsystems:
• controller that includes:
• processor, including a 100 Mbps switch with a built-in PHY, USB 2.0 ports, PCI-E controllers,
8 PCM channels for VoIP applications;
• flash memory — 512 MB;
• SDRAM RAM — 512 MB.
• 8 × subscriber units;
• Ethernet module MGMT: RJ-45 10/100BASE-T;
• Ethernet WAN module: RJ-45 10/100BASE-T;
• USB Host port.

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Block diagram of the device is shown in Figure 2.
Figure 2 — TAU-8N.IP block diagram
The device is running the Linux operating system. Basic control functions are performed by productive
processor which enables IP packet routing, VoIP operation, etc.
The device may functionally be divided into 3 blocks:
• Device network features block;
• VoIP block;
• Control block (Linux operating system).
Device network features block enables IP packet passing according to the device routing table. Depending on
the network interface configuration, this block can process both tagged and untagged packets. Supports
protocols DHCP, PPPoE, L2TP.
VoIP block enables SIP operation for transmission of voice signals through the network that features packet
switching. Subscriber’s voice signal is transferred to the SLIC subscriber unit module, where it is converted into
digital form. The digitized signal is transferred to VoIP block to be encoded using one of the selected standards
and is transferred further in the form of digital packets to the controller via the intrasystem backbone. In addition
to voice signals, digital packets contain control and interaction signals.
Control blockbased on Linux operating system monitors operation of all the other blocks and the device
subsystems and manages their interaction.

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Fig. 3 shows TAU-8N.IP functional diagram.
Figure 3 — TAU-8N.IP functional diagram
1.4. Main Specifications
Table 1 shows main device specifications.
Table 1 — Main specifications
VoIP protocols
Supported protocols
SIP
Voice codecs
Codecs
G.729, annex A, annex B, G.711 a, G.711u, G.723.1,
G.726-16, G.726-24, G.726-32, G.726-40, AAL2-G.726-16,
AAL2-G.726-24, AAL2-G.726-32, AAL2-G.726-40
fax transmission: G.711 a, G.711u, T.38
Ethernet WAN interface specifications:
Number of ports
1
Electrical connector
RJ-45
Data rate 10/100 Mbps, autodetection
Supported standards
BASE-T
Ethernet MGMT interface specifications:
Number of interfaces
1
Electrical connector
RJ-45
Data rate 10/100 Mbps, autodetection
Supported standards
BASE-T

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Analogue user port specifications
Number of ports
8
Loop resistance (phone resistance included) up to 1800 Ω
Dialing reception pulse/frequency (DTMF)
Caller ID broadcasting
FSK BELL 202/FSK V.23/DTMF
Control
Remote control web interface, Telnet, SSH, TR-069
Access restriction by password and by IP address
General parameters
Power supply power adapter 12 V DC, 2.0 A
Power consumption up to 14 W (max. current consumption is 1.17 A)
Operating temperature from +5 to +40 °C
Relative humidity at 25 °C up to 80 %
Dimensions (W × H × D) 208 × 38 × 115 mm
Weight 0.3 kg

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1.5. Design
TAU-8N.IP subscriber gateway is enclosed into 208 × 38 × 115 mm plastic housing.
1.5.1. Front Panel of the Device
The TAU-8N.IP front panel appearance is shown in Figure 4.
Figure 4 — TAU-8N.IP front panel appearance
Table 2 — Description of the front panel indicators and controls
Front panel element Description
1 WAN WAN interface indicator
2 MGMT MGMT interface indicator
3 Phone analogue phone indicator
4 USB external USB device operation indicator (USB flash, external HDD)
5 Status device operation status indicator
6 Power device power and activity status indicator

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1.5.2. Rear Panel of the Device
The TAU-8N.IP rear panel appearance is shown in Figure 5.
Figure 5 — TAU-8N.IP rear panel appearance
Table 3 — Description of the rear panel indicators and controls
Rear panel element Description
7 ON/OFF ON/OFF switch
8
12 V Power adapter connector
9
USB
USB port for external USB device connection (USB flash, HDD)
10
Phone
8 × RJ-11 ports for analogue phone connection
11
F A functional key that reboots the device and resets it to factory settings
12
MGMT
10/100BASE-T Ethernet (RJ-45) port for device network management
13 WAN 10/100BASE-T (RJ-45) port for external network connection

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1.6. Light Indication
WAN, MGMT, Phone, USB, Power, Status indicators located on TAU-8N.IP front panel show the device current
status. Table 4lists possible states of the LEDs.
Table 4 — Light indication of TAU-8N.IP states
Indicator Indicator state Device status
WAN
solid (green — 10 Mbps, orange — 100 Mbps) connection between station terminal and subscriber device is
established
flashes packet data transmission via WAN interface
MGMT
solid (green — 10 Mbps, orange — 100 Mbps) connection to the network device is established
flashes packet data transmission via MGMT interface
Phone
green, solid phone is off-hook (line is active)
off phone is on-hook, normal operation
green, flashes at 20 Hz frequency for a second,
then 4 seconds pause incoming call is on the phone port
green, flashes slowly in period subscriber port is not registered at SIP proxy server
green, double short flashes in 3 seconds
intervals
line test is in progress
USB
green, solid USB device is connected
off USB device is not connected
Status
red, solid failed start attempts are over the limit
green, solid system loaded, the Internet is accessible
red, continuous flashing at 10 Hz frequency bootloader is missing
green, flashes at 1 Hz frequency system loaded, the Internet is not accessible
green, red, intermittent flashing reset to factory settings
off device power supply is off
Power
green, solid device power supply is on, normal operation
red, solid device starts up

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1.7. Reset to Factory Settings
In order to reset the device to factory settings, press the 'F' button located on the device side panel when the
device is powered up and hold it until the 'Status' indicator begins to flash red and green intermittently.
Device will be rebooted automatically.
Factory settings:
• DHCP client is launched on WAN interface;
• MGMT interface address — 192.168.1.1;
• subnet mask — 255.255.255.0;
• user name/password for web interface access: admin/password.
1.8. Delivery Package
TAU-8N.IP standard delivery package includes:
• TAU-8N.IP VoIP gateway;
• 220/12 V, 2.0 A power adapter;
• Installation and configuration guide.

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1. DEVICE MANAGEMENT VIA WEB CONFIGURATOR
2.1. Getting Started
In order to start the operation, connect to the device via MGMT interface using a web browser:
1. Open a web browser (hypertext document viewer), for example, Firefox, Opera, Chrome.
2. Enter the device IP address in the browser address bar.
Default IP address of the device — 192.168.1.1; subnet mask — 255.255.255.0.
When the device is successfully detected, username and password request page will be shown in the browser
window.
3. Enter your username into 'Login' and password into 'Password' field.
Factory settings: login — admin; password — password.
4. Click the 'Log in' button. The quick configuration menu will be shown in the browser window.
Change the default user password to avoid unauthorized access to the device. For setting
password for access via web interface, see 'WEB Authentication' Submenu. It is recommended
to write down and store the set passwords in a safe place which is inaccessible for intruders.
Device management must be inaccessible from public networks. Management allocation in a
separate VLAN is described in 'Network Settings' Submenu. Disabling of unused protocol for
management and standard ports changing are described in 'Access' Submenu.
Before working with the device, it is recommended to upgrade the firmware to the current
version (see the 'Firmware Upgrade' Submenu). The current version of the firmware can be
obtained on the Download Center page on the official website of the company or by contacting
the ELTEX Service Center. For technical support contacts and useful links, see the Technical
Support section on the last page of this manual.

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2.2. User Change
There are three user types for the device: admin, user and viewer. Admin (administrator, default password:
password) has the full access to the device: read/write any settings, full device status monitoring. User (non-
privileged user, default password:user) may change their password and configure PPPoE in order to connect
to the Internet, may not access the device status monitoring. Viewer (default password: viewer) may view full
device configuration, may change only their password, may access full device status monitoring.
When you click the 'logout' button, the current user session will be terminated; login window will be
displayed:
To change the access, you should specify the corresponding username and password and click the 'Log in'
button.
2.3. Web Interface Operation Modes
TAU-8N.IP web interface can operate in three modes:
• Monitoring — system monitoring mode — is used to view device operation information: network
connection availability, phone port state, amount of data received/transferred via network interfaces,
etc.;
• Tiles — quick system configuration mode — each tile contains settings grouped by their functions:
Internet, VoIP and System. A tile only displays basic parameters that enable the quickest possible
configuration of a specific device function;
• Preferences — advanced system configuration mode (full configuration mode) — enables full device
configuration.
To switch between web interface modes, use the panel located on the left hand side in web interface. The
panel will open, when you hover your mouse over it:
To proceed from the 'Tiles' mode into 'Preferences', you may also click ‘more’ link in the tile heading.

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2.4. Applying and Discarding Changes Made to Configuration
2.4.1. Applying Configuration
Click the 'Apply' button to save the configuration into the device flash memory and apply
new settings. All settings will be applied without device restart.
The 'Apply' button in the quick configuration menu and the advanced settings menu will appear as follows:
; .
Web interface visual indication of the current status of the setting application process is described in Table 5:
Table 5 — Visual indication of the current status of the setting application process
Appearance Description
When you click the 'Apply' button, settings will be applied and stored into
the device memory. This is indicated by the icon in the tab name and
on the 'Apply' button.
Successful settings saving and application are indicated by the icon in
the tab name.
If the parameter value being specified contains an error, you will see a
message with the reason description and the icon will appear in the
tab name, when you click the 'Apply' button.
2.4.2. Discarding Changes
You may discard changes only until 'Apply' button is clicked. In this case, edited parameters
on the page will be updated with the values currently stored in the device memory. After you
click 'Apply', you will not be able to restore previous settings.
The 'Cancel' button in the quick configuration menu and the advanced settings menu will appear as follows:
; .

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2.5. Quick Configuration Menu
In the quick configuration menu, basic device settings are displayed, see Figure 6.
Figure 6 — Quick configuration menu
Settings are divided into the following tiles:
• Internet — quick Internet access configuration;
• VoIP — quick VoIP configuration;
• System — configuration of access to web interface via WAN port.
2.5.1. Internet
In order to access the Internet, basic settings should be specified in the 'Internet' tile. To specify additional
parameters, go to advanced settings mode by clicking the 'more' link.
• Protocol — select the protocol that will be used for device WAN interface connection to provider
network:
• Static — operation mode where IP address and all the necessary parameters for WAN interface
are assigned statically. When 'Static' type is selected, the following parameters will be available
for editing:
• WAN IP — specify device WAN interface IP address in the provider network;
• Netmask — external subnet mask;
• Default Gateway — address where the packet will be sent to, when route for it is not found in
the routing table;
• 1st DNS Server, 2nd DNS Server — domain name server addresses (allow to identify the IP
address of the device by its domain name). You may leave these fields empty, if they are not
required.
• DHCP — operation mode where IP address, netmask, DNS address, default gateway and other
necessary settings for network operation are automatically obtained from DHCP server.
Supported options:
• 1 — network mask;
• 3 — the default network gateway address;
• 6 — DNS address;
• 12 — device network name;
• 15 — domain name;
• 26 — MTU size;
• 28 — network broadcast address;
• 33 — static routes;
• 42 — NTP server address;
• 43 — specific vendor information;
• 60 — alternative vendor ID;
• 66 — TFTP server address;

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• 67 — firmware file name (to download via TFTP from the server specified in Option 66);
• 82 — DHCP Relay agent information;
• 120 — SIP server outbound;
• 121 — classless static routes.
In Option 60 DHCP request, the device will send vendor information in the following format:
[VENDOR:vendor][DEVICE:device type][HW:hardware version][SN:serial number]
[WAN :WAN interface МАС address ][VERSION :firmware version]
Example:
[VENDOR:Eltex][DEVICE:TAU-8N.IP][HW:1.0][SN:VI23000118] [WAN:A8:F9:4B:03:2A:D0][VERSION:1.4.0]
The list of DHCP options used on each network interface (Internet, VoIP, Management) can be set manually.
You will find the list setup information in the Appendix C.
• PPPoE — operation mode when PPP session is established on WAN interface.
When 'PPPoE' is selected, the following parameters are available for editing:
• User Name — user name for authorization on PPP server;
• Password — password for authorization on PPP server;
• Service-Name — Service-Name tag value in PADI message for PPPoE connection (this
parameter is optional, and configured only on the provider's request);
• Secondary Access — type of access to local network resources. You may select 2 options:
1. DHCP — dynamic access when IP address and all other required parameters are obtained via DHCP;
2. Static — in this case, you should specify access settings manually: IP address, Netmask, DNS Server, Gateway.
• L2TP — operation mode when the Internet access is established via a tunnel, using L2TP. When
'L2TP' is selected, the following parameters will be available for editing:
• L2TP Server — L2TP server address (domain name or IP address in IPv4 format);
• User Name — user name for authorization on L2TP server;
• Password — password for authorization on L2TP server;
• Secondary access — type of access to local network resources and L2TP server. You may
select 2 options:
2. DHCP — dynamic access when IP address and all other required parameters are obtained via DHCP;
3. Static — in this case, L2TP server access settings should be specified manually:
• IP Address — when the static access is used, L2TP server will be accessed from this address;
• Netmask — when the static access is used, subnet mask;
• DNS Server — when the static access is used, local area network DNS;
• Gateway — when the static access is used, gateway for L2TP server access (if necessary).
L2TP allows establishing secure communication link over the Internet between the remote user's computer
and organization's private network. L2TP is based on Point-to-Point Protocol (PPP) and acts as its extension.
First, the OSI model higher level data is encapsulated into PPP, and then into L2TP for tunnel transmission via
public data networks. L2TP may be used not only in IP networks, service messages for tunnel creation and
data transfer use the same format and protocols.
Due to its characteristics, L2TP is an attractive protocol for building virtual networks.
To apply a new configuration and store settings into the device non-volatile memory, click . To discard
changes, click .
To connect the device to the provider network, it is necessary to request the network settings from the
provider. If you use the static settings, select 'Static' value in the 'Protocol' field and fill the 'WAN IP',
'Netmask', 'Default Gateway', '1st DNS Server', and '2nd DNS Server' fields with the corresponding values
obtained from the provider. If devices in the provider network obtain network settings via DHCP, PPPoE, or
L2TP — select the corresponding protocol in the 'Protocol' field and refer to provider's instructions to achieve
complete and correct device configuration.

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2.5.2. VoIP
For VoIP operation, you should specify settings in the 'VoIP' tile. To specify additional parameters, go to
advanced settings mode by clicking the 'more' link.
In the tabs ‘Line 1’ – ‘Line 8’ you may configure the device phone ports ‘
Phone 1’ – ‘Phone 8’ respectively:
• Enable — when checked, the current line is active;
• Number — subscriber number assigned for the phone line;
• User Name — user name for authentication on SIP server;
• Password — password for authentication on SIP server;
In 'SIP' tab, you may configure basic settings for SIP proxy server:
• Proxy Server — network address of a SIP server — device that manages access to provider's phone
network for all subscribers. You may specify IP address as well as the domain name (specify an alternative
SIP server UDP port after the colon (:), default value is 5060);
• Registration — when checked, subscriber port registration will be enabled on the registration server;
• Registration Server — network address of a device that is used for registration of all phone network
subscribers in order to provide them with the communication services (specify an alternative registration
server port after the colon (:), default value is 5060). You may specify IP address as well as the domain
name. Usually, registration server is physically co-located with SIP proxy server (they have the same
address);
• SIP Domain — domain where the device is located (fill in if required), is assigned automatically
when receiving DHCP option 15 or specified manually. A manually specified domain takes
precedence over the DHCP configuration;
To apply a new configuration and store settings into the device non-volatile memory, click . To discard
changes, click .
2.5.3. System
In the 'System' tile, you may configure access to the device web configurator. To specify additional
parameters, go to advanced settings mode by clicking the 'more' link.
Access to web via WAN:
• HTTP — when checked, the WAN port connection to the device web configurator is enabled via
HTTP (insecure connection);
• HTTPS — when checked, the WAN port connection to the device web configurator is enabled via HTTPS
(secure connection).
By default, access to the device web interface is enabled only for MGMT interface.
To apply a new configuration and store settings into the device non-volatile memory, click . To discard
changes, click .

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3.6. Advanced Settings
To proceed to the advanced settings mode, click 'more' link in any title heading or select 'Preferences' item
on the left panel.
3.6.1. Web Interface Basic Elements
Figure 7 shows web configurator basic navigation elements in the advanced settings mode.
Figure 7 — Web configurator navigation elements
User interface window is divided into seven areas:
1. Logged in user name, session termination button in the web interface (logout) for the current
user and drop-down menu for setting language.
2. Menu tabs include submenu tabs grouped by category: Network, VoIP, System.
3. Submenu tabs allow you to control settings field.
4. Web configurator mode changing panel (for more details, see Section 'Web Interface Operation
Modes').
5. Device settings field based on the user selection; allows you to view device settings and enter
configuration data.
6. Configuration management buttons (for more details, see Section 'Applying and Discarding
Changes Made to Configuration':
• Apply — apply and save the current configuration into the device non-volatile memory;
• Cancel — discard changes (you can discard changes only until 'Apply' button is clicked).
7. Informational field showing firmware version and Web interface version.