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12.1.7.2 Use NAT

If you know the NAT router!s public IP address and SIP port number, you can use the Use
NAT feature to manually configure the ZyXEL Device to use a them in the SIP messages. This
eliminates the need for STUN or a SIP ALG.

You must also configure the NAT router to forward traffic with this port number to the ZyXEL Device.

12.1.7.3 STUN

STUN (Simple Traversal of User Datagram Protocol (UDP) through Network Address
Translators) allows the ZyXEL Device to find the presence and types of NAT routers and/or
firewalls between it and the public Internet. STUN also allows the ZyXEL Device to find the
public IP address that NAT assigned, so the ZyXEL Device can embed it in the SIP data
stream. STUN does not work with symmetric NAT routers or firewalls. See RFC 3489 for
details on STUN.

The following figure shows how STUN works.

1 The ZyXEL Device (A) sends SIP packets to the STUN server (B).
2 The STUN server (B) finds the public IP address and port number that the NAT router

used on the ZyXEL Device!s SIP packets and sends them to the ZyXEL Device.

3 The ZyXEL Device uses the public IP address and port number in the SIP packets that it

sends to the SIP server (C).

Figure 102 STUN

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12.1.7.4 Outbound Proxy

Your VoIP service provider may host a SIP outbound proxy server to handle all of the ZyXEL
Device!s VoIP traffic. This allows the ZyXEL Device to work with any type of NAT router and
eliminates the need for STUN or a SIP ALG. Turn off a SIP ALG on a NAT router in front of
the ZyXEL Device to keep it from retranslating the IP address (since this is already handled by
the outbound proxy server).

12.1.8 Voice Coding

A codec (coder/decoder) codes analog voice signals into digital signals and decodes the digital
signals back into voice signals. The ZyXEL Device supports the following codecs.

G.711 is a Pulse Code Modulation (PCM) waveform codec. PCM measures analog signal

amplitudes at regular time intervals (sampling) and converts them into digital bits
(quantization). Quantization "reads# the analog signal and then "writes# it to the nearest
digital value. For this reason, a digital sample is usually slightly different from its analog
original (this difference is known as "quantization noise#).

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G.711 provides excellent sound quality but requires 64kbps of bandwidth.

G.723 is an Adaptive Differential Pulse Code Modulation (ADPCM) waveform codec.

Differential (or Delta) PCM is similar to PCM, but encodes the audio signal based on the
difference between one sample and a prediction based on previous samples, rather than
encoding the sample!s actual quantized value. Many thousands of samples are taken each
second, and the differences between consecutive samples are usually quite small, so this
saves space and reduces the bandwidth necessary.

However, DPCM produces a high quality signal (high signal-to-noise ratio or SNR) for
high difference signals (where the actual signal is very different from what was predicted)
but a poor quality signal (low SNR) for low difference signals (where the actual signal is
very similar to what was predicted). This is because the level of quantization noise is the
same at all signal levels. Adaptive DPCM solves this problem by adapting the difference
signal!s level of quantization according to the audio signal!s strength. A low difference
signal is given a higher quantization level, increasing its signal-to-noise ratio. This
provides a similar sound quality at all signal levels.

G.723 provides high quality sound and requires 20 or 40 kbps.

G.729 is an Analysis-by-Synthesis (AbS) hybrid waveform codec. It uses a filter based on

information about how the human vocal tract produces sounds. The codec analyzes the
incoming voice signal and attempts to synthesize it using its list of voice elements. It tests
the synthesized signal against the original and, if it is acceptable, transmits details of the
voice elements it used to make the synthesis. Because the codec at the receiving end has
the same list, it can exactly recreate the synthesized audio signal.

G.729 provides good sound quality and reduces the required bandwidth to 8kbps.

12.1.9 PSTN Call Setup Signaling

PSTNs (Public Switched Telephone Networks) use DTMF or pulse dialing to set up telephone
calls.

Dual-Tone Multi-Frequency (DTMF) signaling uses pairs of frequencies (one lower frequency
and one higher frequency) to set up calls. It is also known as Touch Tone? Each of the keys
on a DTMF telephone corresponds to a different pair of frequencies.

Pulse dialing sends a series of clicks to the local phone office in order to dial numbers.

12.1.10 MWI (Message Waiting Indication)

Enable Message Waiting Indication (MWI) enables your phone to give you a message%waiting
(beeping) dial tone when you have one or more voice messages. Your VoIP service provider
must have a messaging system that sends message-waiting-status SIP packets as defined in
RFC 3842.

3.The ZyXEL Device supports DTMF at the time of writing.

3

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12.1.11 Custom Tones (IVR)

IVR (Interactive Voice Response) is a feature that allows you to use your telephone to interact
with the ZyXEL Device. The ZyXEL Device allows you to record custom tones for the Caller
Ringing Tone and On Hold Tone functions. The same recordings apply to both the caller
ringing and on hold tones.

Table 58 Custom Tones Details

LABEL DESCRIPTION

Total Time for All Tones128 seconds for all custom tones combined

Maximum Time per
Individual Tone

Total Number of Tones
Recordable

12.1.11.1 Recording Custom Tones

Use the following steps if you would like to create new tones or change your tones:

1 Pick up the phone and press **** on your phone!s keypad and wait for the message that

says you are in the configuration menu.

2 Press a number from 1101~1108 on your phone followed by the # key.
3 Play your desired music or voice recording into the receiver!s mouthpiece. Press the #

key.

4 You can continue to add, listen to, or delete tones, or you can hang up the receiver when

you are done.

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20 seconds

8
You can record up to eight different custom tones but the total time must

be 128 seconds or less.

12.1.11.2 Listening to Custom Tones

Do the following to listen to a custom tone:

1 Pick up the phone and press **** on your phone!s keypad and wait for the message that

says you are in the configuration menu.

2 Press a number from 1201~1208 followed by the # key to listen to the tone.
3 You can continue to add, listen to, or delete tones, or you can hang up the receiver when

you are done.

12.1.11.3 Deleting Custom Tones

Do the following to delete a custom tone:

1 Pick up the phone and press **** on your phone!s keypad and wait for the message that

says you are in the configuration menu.

2 Press a number from 1301~1308 followed by the # key to delete the tone of your choice.

Press 14 followed by the # key if you wish to clear all your custom tones.

3 You can continue to add, listen to, or delete tones, or you can hang up the receiver when

you are done.

12.1.12 Quality of Service (QoS)

Quality of Service (QoS) refers to both a network's ability to deliver data with minimum delay
and the networking methods used to provide bandwidth for real-time multimedia applications.

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12.1.12.1 Type Of Service (ToS)

Network traffic can be classified by setting the ToS (Type Of Service) values at the data source
(for example, at the ZyXEL Device) so a server can decide the best method of delivery, that is
the least cost, fastest route and so on.

12.1.12.2 DiffServ

DiffServ is a class of service (CoS) model that marks packets so that they receive specific per­hop treatment at DiffServ-compliant network devices along the route based on the application
types and traffic flow. Packets are marked with DiffServ Code Points (DSCPs) indicating the
level of service desired. This allows the intermediary DiffServ-compliant network devices to
handle the packets differently depending on the code points without the need to negotiate paths
or remember state information for every flow. In addition, applications do not have to request
a particular service or give advanced notice of where the traffic is going.

12.1.12.3 DSCP and Per-Hop Behavior

DiffServ defines a new DS (Differentiated Services) field to replace the Type of Service (TOS)
field in the IP header. The DS field contains a 2-bit unused field and a 6-bit DSCP field which
can define up to 64 service levels. The following figure illustrates the DS field.

Figure 103 DiffServ: Differentiated Service Field

4

DSCP
(6-bit)

DSCP is backward compatible with the three precedence bits in the ToS octet so that non­DiffServ compliant, ToS-enabled network device will not conflict with the DSCP mapping.

The DSCP value determines the forwarding behavior, the PHB (Per-Hop Behavior), that each
packet gets across the DiffServ network. Based on the marking rule, different kinds of traffic
can be marked for different priorities of forwarding. Resources can then be allocated
according to the DSCP values and the configured policies.

12.1.12.4 VLAN

Virtual Local Area Network (VLAN) allows a physical network to be partitioned into multiple
logical networks. Only stations within the same group can communicate with each other.

Your ZyXEL Device can add IEEE 802.1Q VLAN ID tags to voice frames that it sends to the
network. This allows the ZyXEL Device to communicate with a SIP server that is a member of
the same VLAN group. Some ISPs use the VLAN tag to identify voice traffic and give it
priority over other traffic.

Unused
(2-bit)

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4.The ZyXEL Device does not support DiffServ at the time of writing.

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12.2 SIP Screens

12.2.1 SIP Settings Screen

Use this screen to maintain basic information about each SIP account. Your VoIP service
provider (the company that lets you make phone calls over the Internet) should provide this.
You can also enable and disable each SIP account. To access this screen, click VoIP > SIP >
SIP Settings.

Figure 104 VoIP > SIP > SIP Settings

Chapter 12SIP

Each field is described in the following table.

Table 59 VoIP > SIP > SIP Settings

LABEL DESCRIPTION

SIP Account Select the SIP account you want to see in this screen. If you change this field, the

SIP Settings

Active SIP
Account

NumberEnter your SIP number. In the full SIP URI, this is the part before the @ symbol.

SIP Local PortEnter the ZyXEL Device s listening port number, if your VoIP service provider gave

SIP Server
Address

SIP Server PortEnter the SIP server s listening port number, if your VoIP service provider gave

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screen automatically refreshes.

Select this if you want the ZyXEL Device to use this account. Clear it if you do not
want the ZyXEL Device to use this account.

You can use up to 127 printable ASCII characters.

you one. Otherwise, keep the default value.

Enter the IP address or domain name of the SIP server provided by your VoIP
service provider. You can use up to 95 printable ASCII characters. It does not
matter whether the SIP server is a proxy, redirect or register server.

you one. Otherwise, keep the default value.

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Table 59 VoIP > SIP > SIP Settings

LABEL DESCRIPTION

REGISTER
Server Address

REGISTER
Server Port

SIP Service
Domain

Send Caller IDSelect this if you want to send identification when you make VoIP phone calls.

Authentication

User NameEnter the user name for registering this SIP account, exactly as it was given to

PasswordEnter the user name for registering this SIP account, exactly as it was given to

Apply Click this to save your changes.

Reset Click this to set every field in this screen to its last-saved value.

Advanced Setup Click this to edit the advanced settings for this SIP account. The Advanced SIP

Enter the IP address or domain name of the SIP register server, if your VoIP
service provider gave you one. Otherwise, enter the same address you entered in
the SIP Server Address field. You can use up to 95 printable ASCII characters.

Enter the SIP register server s listening port number, if your VoIP service provider
gave you one. Otherwise, enter the same port number you entered in the SIP
Server Port field.

Enter the SIP service domain name. In the full SIP URI, this is the part after the @
symbol. You can use up to 127 printable ASCII Extended set characters.

Clear this if you do not want to send identification.

you. You can use up to 95 printable ASCII characters.

you. You can use up to 95 printable ASCII Extended set characters.

Setup screen appears.

12.2.2 Advanced SIP Setup Screen

Use this screen to maintain advanced settings for each SIP account. To access this screen, click
Advanced Setup in VoIP > SIP > SIP Settings.

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Figure 105 VoIP > SIP > SIP Settings > Advanced

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Each field is described in the following table.

Table 60 VoIP > SIP > SIP Settings > Advanced

LABEL DESCRIPTION

SIP AccountThis field displays the SIP account you see in this screen.

SIP Server
Settings

URL TypeSelect whether or not to include the SIP service domain name when the ZyXEL

Expiration
Duration

Register Re-send
timer

Session ExpiresEnter the number of seconds the conversation can last before the call is

Min-SEEnter the minimum number of seconds the ZyXEL Device accepts for a session

RTP Port Range

Start Port
End Port

Voice
Compression

Primary
Compression
Type

Secondary
Compression
Type

Third
Compression
Type

Device sends the SIP number.

SIP - include the SIP service domain name
TEL - do not include the SIP service domain name

Enter the number of seconds your SIP account is registered with the SIP register
server before it is deleted. The ZyXEL Device automatically tries to re-register
your SIP account when one-half of this time has passed. (The SIP register server
might have a different expiration.)

Enter the number of seconds the ZyXEL Device waits before it tries again to
register the SIP account, if the first try failed or if there is no response.

automatically disconnected. Usually, when one-half of this time has passed, the
ZyXEL Device or the other party updates this timer to prevent this from happening.

expiration time when it receives a request to start a SIP session. If the request has
a shorter time, the ZyXEL Device rejects it.

Enter the listening port number(s) for RTP traffic, if your VoIP service provider
gave you this information. Otherwise, keep the default values.

To enter one port number, enter the port number in the Start Port and End Port
fields.

To enter a range of ports,

# enter the port number at the beginning of the range in the Start Port field
# enter the port number at the end of the range in the End Port field.

Select the type of voice coder/decoder (codec) that you want the ZyXEL Device to
use.

G.711 provides high voice quality but requires more bandwidth (64 kbps).

# G.711A is typically used in Europe.
# G.711u is typically used in North America and Japan.

G.723 provides good voice quality, and requires 20 or 40 kbps.
In contrast, G.729 requires only 8 kbps.
The ZyXEL Device must use the same codec as the peer. When two SIP devices

start a SIP session, they must agree on a codec.

Select the ZyXEL Device s first choice for voice coder/decoder.

Select the ZyXEL Device s second choice for voice coder/decoder. Select None if
you only want the ZyXEL Device to accept the first choice.

This field is disabled if Secondary Compression Type is None.
Select the ZyXEL Device s third choice for voice coder/decoder. Select None if

you only want the ZyXEL Device to accept the first or second choice.

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Table 60 VoIP > SIP > SIP Settings > Advanced

LABEL DESCRIPTION

DTMF Mode Control how the ZyXEL Device handles the tones that your telephone makes

STUN

ActiveSelect this if all of the following conditions are satisfied.

Server AddressEnter the IP address or domain name of the STUN server provided by your VoIP

Server PortEnter the STUN server s listening port, if your VoIP service provider gave you one.

Use NAT

ActiveSelect this if you want the ZyXEL Device to send SIP traffic to a specific NAT

Server AddressEnter the public IP address or domain name of the NAT router.

Server PortEnter the port number that your SIP sessions use with the public IP address of the

Outbound Proxy

ActiveSelect this if your VoIP service provider has a SIP outbound server to handle voice

Server AddressEnter the IP address or domain name of the SIP outbound proxy server.

Server PortEnter the SIP outbound proxy server s listening port, if your VoIP service provider

NAT Keep Alive

ActiveSelect this to stop NAT routers between the ZyXEL Device and SIP server (a SIP

Keep Alive with
SIP Proxy

Keep Alive with
Outbound Proxy

Keep Alive
Interval

MWI (Message
Waiting
Indication)

when you push its buttons. You should use the same mode your VoIP service
provider uses.

RFC 2833 - send the DTMF tones in RTP packets
PCM - send the DTMF tones in the voice data stream. This method works best

when you are using a codec that does not use compression (like G.711). Codecs
that use compression (like G.729) can distort the tones.

SIP INFO - send the DTMF tones in SIP messages

# There is a NAT router between the ZyXEL Device and the SIP server.
# The NAT router is not a SIP ALG.
# Your VoIP service provider gave you an IP address or domain name for a

STUN server.

Otherwise, clear this field.

service provider.

Otherwise, keep the default value.

router. You must also configure the NAT router to forward traffic with the specified
port to the ZyXEL Device. This eliminates the need for STUN or a SIP ALG.

NAT router.

calls. This allows the ZyXEL Device to work with any type of NAT router and
eliminates the need for STUN or a SIP ALG. Turn off any SIP ALG on a NAT router
in front of the ZyXEL Device to keep it from retranslating the IP address (since this
is already handled by the outbound proxy server).

gave you one. Otherwise, keep the default value.

proxy server or outbound proxy server) from dropping the SIP session. The ZyXEL
Device does this by sending SIP notify messages to the SIP server based on the
specified interval.

Select this if the SIP server is a SIP proxy server.

Select this if the SIP server is an outbound proxy server. You must enable
Outbound Proxy to use this.

Enter how often (in seconds) the ZyXEL Device should send SIP notify messages
to the SIP server.

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Table 60 VoIP > SIP > SIP Settings > Advanced

LABEL DESCRIPTION

EnableSelect this if you want to hear a waiting (beeping) dial tone on your phone when

Expiration TimeKeep the default value, unless your VoIP service provider tells you to change it.

Fax OptionThis field controls how the ZyXEL Device handles fax messages.

G.711 Fax
Passthrough

T.38 Fax RelaySelect this if the ZyXEL Device should send fax messages as UDP or TCP/IP

Call Forward

Call Forward
Table

Caller Ringing

EnableCheck this box if you want people to hear a customized recording when they call

Caller Ringing
Tone

On Hold

EnableCheck this box if you want people to hear a customized recording when you put

On Hold ToneSelect the tone you want people to hear when you put them on hold. See Section

<BackClick this to return to the SIP Settings screen without saving your changes.

Apply Click this to save your changes.

Reset Click this to set every field in this screen to its last-saved value.

you have at least one voice message. Your VoIP service provider must support
this feature.

Enter the number of seconds the SIP server should provide the message waiting
service each time the ZyXEL Device subscribes to the service. Before this time
passes, the ZyXEL Device automatically subscribes again.

Select this if the ZyXEL Device should use G.711 to send fax messages. The peer
devices must also use G.711.

packets through IP networks. This provides better quality, but it may have inter­operability problems. The peer devices must also use T.38.

Select which call forwarding table you want the ZyXEL Device to use for incoming
calls. You set up these tables in VoIP > Phone Book > Incoming Call Policy.

you.

Select the tone you want people to hear when they call you. See Section 12.1.11

on page 155 for information on how to record these tones.

them on hold.

12.1.11 on page 155 for information on how to record these tones.

12.2.3 SIP QoS Screen

Use this screen to maintain ToS and VLAN settings for the ZyXEL Device. To access this
screen, click VoIP > SIP > QoS.

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Figure 106 VoIP > SIP > QoS

Each field is described in the following table.

Table 61 VoIP > SIP > QoS

LABEL DESCRIPTION

SIP TOS Priority
Setting

RTP TOS Priority
Setting

Voice VLAN IDSelect this if the ZyXEL Device has to be a member of a VLAN to communicate

Apply Click this to save your changes.

Reset Click this to set every field in this screen to its last-saved value.

Enter the priority for SIP voice transmissions. The ZyXEL Device creates Type of
Service priority tags with this priority to voice traffic that it transmits.

Enter the priority for RTP voice transmissions. The ZyXEL Device creates Type of
Service priority tags with this priority to RTP traffic that it transmits.

with the SIP server. Ask your network administrator, if you are not sure. Enter the
VLAN ID provided by your network administrator in the field on the right. Your LAN
and gateway must be configured to use VLAN tags.

Otherwise, clear this field.

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CHAPTER 13

Phone

Use these screens to configure the phone you use to make phone calls with the ZyXEL Device.

13.1 Phone Overview

You can configure the volume, echo cancellation, VAD settings and custom tones for the
phone port on the ZyXEL Device. You can also select which SIP account to use for making
outgoing calls.

13.1.1 Voice Activity Detection/Silence Suppression/Comfort Noise

Voice Activity Detection (VAD) detects whether or not speech is present. This lets the ZyXEL
Device reduce the bandwidth that a call uses by not transmitting "silent packets# when you are
not speaking.

When using VAD, the ZyXEL Device generates comfort noise when the other party is not
speaking. The comfort noise lets you know that the line is still connected as total silence could
easily be mistaken for a lost connection.

13.1.2 Echo Cancellation

G.168 is an ITU-T standard for eliminating the echo caused by the sound of your voice
reverberating in the telephone receiver while you talk.

13.1.3 Supplementary Phone Services Overview

Supplementary services such as call hold, call waiting, call transfer, etc. are generally
available from your VoIP service provider. The ZyXEL Device supports the following
services:

Call Hold
Call Waiting
Making a Second Call
Call Transfer
Call Forwarding
Three-Way Conference
Internal Calls
Caller ID
CLIP (Calling Line Identification Presentation)

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Chapter 13Phone

CLIR (Calling Line Identification Restriction)

To take full advantage of the supplementary phone services available though
the ZyXEL Device's phone port, you may need to subscribe to the services
from your VoIP service provider.

13.1.3.1 The Flash Key

Flashing means to press the hook for a short period of time (a few hundred milliseconds)
before releasing it. On newer telephones, there should be a "flash" key (button) that generates
the signal electronically. If the flash key is not available, you can tap (press and immediately
release) the hook by hand to achieve the same effect. However, using the flash key is preferred
since the timing is much more precise. The ZyXEL Device may interpret manual tapping as
hanging up if the duration is too long

You can invoke all the supplementary services by using the flash key.

13.1.3.2 Europe Type Supplementary Phone Services

This section describes how to use supplementary phone services with the Europe TypeCall
Service Mode. Commands for supplementary services are listed in the table below.

After pressing the flash key, if you do not issue the sub-command before the default sub­command timeout (2 seconds) expires or issue an invalid sub-command, the current operation
will be aborted.

Table 62 European Type Flash Key Commands

COMMAND SUB-COMMAND DESCRIPTION

Flash Put a current call on hold to place a second call.

Switch back to the call (if there is no second call).

Flash0Drop the call presently on hold or reject an incoming call which is

Flash1Disconnect the current phone connection and answer the

Flash21. Switch back and forth between two calls.

Flash3Create three-way conference connection.

Flash *98#Transfer the call to another phone.

waiting for answer.

incoming call or resume with caller presently on hold.

2. Put a current call on hold to answer an incoming call.

3. Separate the current three-way conference call into two
individual calls (one is on-line, the other is on hold).

13.1.3.2.1 European Call Hold

Call hold allows you to put a call (A) on hold by pressing the flash key.

If you have another call, press the flash key and then "2# to switch back and forth between
caller A and B by putting either one on hold.

Press the flash key and then "0# to disconnect the call presently on hold and keep the current
call on line.

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Press the flash key and then "1# to disconnect the current call and resume the call on hold.

If you hang up the phone but a caller is still on hold, there will be a remind ring.

13.1.3.2.2 European Call Waiting

This allows you to place a call on hold while you answer another incoming call on the same
telephone (directory) number.

If there is a second call to a telephone number, you will hear a call waiting tone. Take one of
the following actions.

Reject the second call.

Press the flash key and then press "0#.

Disconnect the first call and answer the second call.

Either press the flash key and press "1#, or just hang up the phone and then answer the
phone after it rings.

Put the first call on hold and answer the second call.

Press the flash key and then "2#.

13.1.3.2.3 European Call Transfer

Do the following to transfer an incoming call (that you have answered) to another phone.

1 Press the flash key to put the caller on hold.
2 When you hear the dial tone, dial "*98## followed by the number to which you want to

transfer the call. to operate the Intercom.

3 After you hear the ring signal or the second party answers it, hang up the phone.

Chapter 13Phone

13.1.3.2.4 European Three-Way Conference

Use the following steps to make three-way conference calls.

1 When you are on the phone talking to someone, place the flash key to put the caller on

hold and get a dial tone.

2 Dial a phone number directly to make another call.
3 When the second call is answered, press the flash key and press "3# to create a three-way

conversation.

4 Hang up the phone to drop the connection.
5 If you want to separate the activated three-way conference into two individual

connections (one is on-line, the other is on hold), press the flash key and press "2#.

13.1.3.3 USA Type Supplementary Services

This section describes how to use supplementary phone services with the USA TypeCall
Service Mode. Commands for supplementary services are listed in the table below.

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After pressing the flash key, if you do not issue the sub-command before the default sub­command timeout (2 seconds) expires or issue an invalid sub-command, the current operation
will be aborted.

Table 63 USA Type Flash Key Commands

COMMAND SUB-COMMAND DESCRIPTION

Flash Put a current call on hold to place a second call. After the second

Flash *98#Transfer the call to another phone.

13.1.3.3.1 USA Call Hold

Call hold allows you to put a call (A) on hold by pressing the flash key.

If you have another call, press the flash key to switch back and forth between caller A and B
by putting either one on hold.

If you hang up the phone but a caller is still on hold, there will be a remind ring.

13.1.3.3.2 USA Call Waiting

This allows you to place a call on hold while you answer another incoming call on the same
telephone (directory) number.

If there is a second call to your telephone number, you will hear a call waiting tone.

Press the flash key to put the first call on hold and answer the second call.

call is successful, press the flash key again to have a three-way
conference call.

Put a current call on hold to answer an incoming call.

13.1.3.3.3 USA Call Transfer

Do the following to transfer an incoming call (that you have answered) to another phone.

1 Press the flash key to put the caller on hold.
2 When you hear the dial tone, dial "*98## followed by the number to which you want to

transfer the call. to operate the Intercom.

3 After you hear the ring signal or the second party answers it, hang up the phone.

13.1.3.3.4 USA Three-Way Conference

Use the following steps to make three-way conference calls.

1 When you are on the phone talking to someone, place the flash key to put the caller on

hold and get a dial tone.

2 Dial a phone number directly to make another call.
3 When the second call is answered, press the flash key, wait for the sub-command tone

and press "3# to create a three-way conversation.

4 Hang up the phone to drop the connection.
5 If you want to separate the activated three-way conference into two individual

connections (one is on-line, the other is on hold), press the flash key, wait for the sub­command tone and press "2#.

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13.2 Phone Screens

13.2.1 Analog Phone Screen

Use this screen to control which SIP accounts and PSTN line each phone uses. To access this
screen, click VoIP > Phone > Analog Phone.

Figure 107 VoIP > Phone > Analog Phone

Chapter 13Phone

Each field is described in the following table.

Table 64 VoIP > Phone > Analog Phone

LABEL DESCRIPTION

Phone Port
Settings

Outgoing Call Use

SIP1Select this if you want this phone port to use the SIP1 account when it makes

SIP2Select this if you want this phone port to use the SIP2 account when it makes

Incoming Call
apply to

SIP1Select this if you want to receive phone calls for the SIP1 account on this phone

SIP2Select this if you want to receive phone calls for the SIP2 account on this phone

Apply Click this to save your changes.

Reset Click this to set every field in this screen to its last-saved value.

Advanced Setup Click this to edit the advanced settings for this phone port. The Advanced Analog

Select the phone port you want to see in this screen. If you change this field, the
screen automatically refreshes.

calls. If you select both SIP accounts, the ZyXEL Device tries to use SIP2 first.

calls. If you select both SIP accounts, the ZyXEL Device tries to use SIP2 first.

port. If you select more than one source for incoming calls, there is no way to
distinguish between them when you receive phone calls.

port. If you select more than one source for incoming calls, there is no way to
distinguish between them when you receive phone calls.

Phone Setup screen appears.

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13.2.2 Advanced Analog Phone Setup Screen

Use this screen to edit advanced settings for each phone port. To access this screen, click
Advanced Setup in VoIP > Phone > Analog Phone.

Figure 108 VoIP > Phone > Analog Phone > Advanced

Each field is described in the following table.

Table 65 VoIP > Phone > Analog Phone > Advanced

LABEL DESCRIPTION

Analog Phone This field displays the phone port you see in this screen.

Voice Volume
Control

Speaking VolumeEnter the loudness that the ZyXEL Device uses for speech that it sends to the

Listening VolumeEnter the loudness that the ZyXEL Device uses for speech that it receives from

Echo Cancellation

G.168 ActiveSelect this if you want to eliminate the echo caused by the sound of your voice

Dialing Interval
Select

Dialing Interval
Select

VAD SupportSelect this if the ZyXEL Device should stop transmitting when you are not

<BackClick this to return to the Analog Phone screen without saving your changes.

Apply Click this to save your changes and to apply them to the ZyXEL Device.

Reset Click this to set every field in this screen to its last-saved value.

peer device. -1 is the quietest, and 1 is the loudest.

the peer device. -1 is the quietest, and 1 is the loudest.

reverberating in the telephone receiver while you talk.

Enter the number of seconds the ZyXEL Device should wait after you stop dialing
numbers before it makes the phone call. The value depends on how quickly you
dial phone numbers.

If you select Active Immediate Dial in VoIP > Phone > Common, you can press
the pound key (#) to tell the ZyXEL Device to make the phone call immediately,
regardless of this setting.

speaking. This reduces the bandwidth the ZyXEL Device uses.

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13.2.3 Common Phone Settings Screen

Use this screen to activate and deactivate immediate dialing. To access this screen, click VoIP
> Phone > Common.

Figure 109 VoIP > Phone > Common

Each field is described in the following table.

Table 66 VoIP > Phone > Common

LABEL DESCRIPTION

Active Immediate
Dial

Apply Click this to save your changes.

Reset Click this to set every field in this screen to its last-saved value.

Select this if you want to use the pound key (#) to tell the ZyXEL Device to make
the phone call immediately, instead of waiting the number of seconds you selected
in the Dialing Interval Select in VoIP > Phone > Analog Phone.

If you select this, dial the phone number, and then press the pound key if you do
not want to wait. The ZyXEL Device makes the call immediately.

Chapter 13Phone

13.2.4 Phone Region Screen

Use this screen to maintain settings that often depend on which region of the world the ZyXEL
Device is in. To access this screen, click VoIP > Phone > Region.

Figure 110 VoIP > Phone > Region

Each field is described in the following table.

Table 67 VoIP > Phone > Region

LABEL DESCRIPTION

Region Settings Select the place in which the ZyXEL Device is located. Do not select Default.

Call Service Mode Select the mode for supplementary phone services (call hold, call waiting, call

transfer and three-way conference calls) that your VoIP service provider supports.

Europe Type - use supplementary phone services in European mode
USA Type - use supplementary phone services American mode

You might have to subscribe to these services to use them. Contact your VoIP
service provider.

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Table 67 VoIP > Phone > Region

LABEL DESCRIPTION

Apply Click this to save your changes and to apply them to the ZyXEL Device.

Reset Click this to set every field in this screen to its last-saved value.

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CHAPTER 14

Phone Book

Use these screens to maintain call-forwarding rules and speed-dial settings.

14.1 Phone Book Overview

Speed dial provides shortcuts for dialing frequently used (VoIP) phone numbers. It is also
required if you want to make peer-to-peer calls. In peer-to-peer calls, you call another VoIP
device directly without going through a SIP server. In the ZyXEL Device, you must set up a
speed dial entry in the phone book in order to do this. Select Non-Proxy (Use IP or URL) in
the Type column and enter the callee!s IP address or domain name. The ZyXEL Device sends
SIP INVITE requests to the peer VoIP device when you use the speed dial entry.

You do not need to configure a SIP account in order to make a peer-to-peer VoIP call.

14.2 Phone Book Screens

14.2.1 Incoming Call Policy Screen

Use this screen to maintain rules for handling incoming calls. You can block, redirect, or
accept them. To access this screen, click VoIP > Phone Book > Incoming Call Policy.

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Figure 111 VoIP > Phone Book > Incoming Call Policy

You can create two sets of call-forwarding rules. Each one is stored in a call-forwarding table.
Each field is described in the following table.

Table 68 VoIP > Phone Book > Incoming Call Policy

LABEL DESCRIPTION

Table Number Select the call-forwarding table you want to see in this screen. If you change this

Forward to
Number Setup

Unconditional
Forward to
Number

Busy Forward to
Number

No Answer
Forward to
Number

No Answer
Waiting Time

Advanced SetupThe ZyXEL Device checks these rules before it checks the rules in the Forward to

field, the screen automatically refreshes.

The ZyXEL Device checks these rules, in the order in which they appear, after it
checks the rules in the Advanced Setup section.

Select this if you want the ZyXEL Device to forward all incoming calls to the
specified phone number, regardless of other rules in the Forward to Number
section. Specify the phone number in the field on the right.

Select this if you want the ZyXEL Device to forward incoming calls to the specified
phone number if the phone port is busy. Specify the phone number in the field on
the right. If you have call waiting, the incoming call is forwarded to the specified
phone number if you reject or ignore the second incoming call.

Select this if you want the ZyXEL Device to forward incoming calls to the specified
phone number if the call is unanswered. (See No Answer Waiting Time.) Specify
the phone number in the field on the right.

This field is used by the No Answer Forward to Number feature and No Answer
conditions below.

Enter the number of seconds the ZyXEL Device should wait for you to answer an
incoming call before it considers the call is unanswered.

Number section.

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Chapter 14Phone Book

Table 68 VoIP > Phone Book > Incoming Call Policy

LABEL DESCRIPTION

#This field is a sequential value, and it is not associated with a specific rule. The

ActivateSelect this to enable this rule. Clear this to disable this rule.

Incoming Call
Number

Forward to
Number

ConditionSelect the situations in which you want to forward incoming calls from the

Apply Click this to save your changes and to apply them to the ZyXEL Device.

Reset Click this to set every field in this screen to its last-saved value.

sequence is important, however. The ZyXEL Device checks each rule in order,
and it only follows the first one that applies.

Enter the phone number to which this rule applies.

Enter the phone number to which you want to forward incoming calls from the

Incoming Call Number. You may leave this field blank, depending on the
Condition.

Incoming Call Number, or select an alternative action.
Unconditional - The ZyXEL Device immediately forwards any calls from the

Incoming Call Number to the Forward to Number.
Busy - The ZyXEL Device forwards any calls from the Incoming Call Number to

the Forward to Number when your SIP account already has a call connected.
No Answer - The ZyXEL Device forwards any calls from the Incoming Call

Number to the Forward to Number when the call is unanswered. (See No
Answer Waiting Time.)

Block - The ZyXEL Device rejects calls from the Incoming Call Number.
Accept - The ZyXEL Device allows calls from the Incoming Call Number. You

might create a rule with this condition if you do not want incoming calls from
someone to be forwarded by rules in the Forward to Number section.

14.2.2 Speed Dial Screen

You have to create speed-dial entries if you want to make peer-to-peer calls or call SIP
numbers that use letters. You can also create speed-dial entries for frequently-used SIP phone
numbers. Use this screen to add, edit, or remove speed-dial entries. To access this screen, click
VoIP > Phone Book > Speed Dial.

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Figure 112 VoIP > Phone Book > Speed Dial

Each field is described in the following table.

Table 69 VoIP > Phone Book > Speed Dial

LABEL DESCRIPTION

Speed Dial Use this section to create or edit speed-dial entries.

Speed Dial Select the speed-dial number you want to use for this phone number.

NumberEnter the SIP number you want the ZyXEL Device to call when you dial the speed-

NameEnter a name to identify the party you call when you dial the speed-dial number.

TypeSelect Use Proxy if you want to use one of your SIP accounts to call this phone

AddClick this to use the information in the Speed Dial section to update the Speed

Speed Dial Phone
Book

Speed DialThis field displays the speed-dial number you should dial to use this entry. You

NumberThis field displays the SIP number the ZyXEL Device calls when you dial the

NameThis field displays the name of the party you call when you dial the speed-dial

DestinationThis field is blank, if the speed-dial entry uses one of your SIP accounts.

dial number.

You can use up to 127 printable ASCII characters.

number.
Select Non-Proxy (Use IP or URL) if you want to use a different SIP server or if

you want to make a peer-to-peer call. In this case, enter the IP address or domain
name of the SIP server or the other party in the field below.

Dial Phone Book section.

Use this section to look at all the speed-dial entries and to erase them.

should dial the numbers the way they appear in the screen.

speed-dial number.

number.

Otherwise, this field shows the IP address or domain name of the SIP server or
other party. (This field corresponds with the Type field in the Speed Dial section.)

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Table 69 VoIP > Phone Book > Speed Dial

LABEL DESCRIPTION

ModifyUse this field to edit or erase the speed-dial entry.

Click the Edit icon to copy the information for this speed-dial entry into the Speed
Dial section, where you can change it.

Click the Remove icon to erase this speed-dial entry.

Clear Click this to erase all the speed-dial entries.

Reset Click this to set every field in this screen to its last-saved value.

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CHAPTER 15

Firewall

Use these screens to enable, configure and disable the firewall that protects your ZyXEL
Device and your LAN from unwanted or malicious traffic.

15.1 Firewall Overview

Originally, the term firewall referred to a construction technique designed to prevent the
spread of fire from one room to another. The networking term "firewall" is a system or group
of systems that enforces an access-control policy between two networks. It may also be
defined as a mechanism used to protect a trusted network from an untrusted network. Of
course, firewalls cannot solve every security problem. A firewall is one of the mechanisms
used to establish a network security perimeter in support of a network security policy. It should
never be the only mechanism or method employed. For a firewall to guard effectively, you
must design and deploy it appropriately. This requires integrating the firewall into a broad
information-security policy. In addition, specific policies must be implemented within the
firewall itself.

15.1.1 Stateful Inspection Firewall.

Stateful inspection firewalls restrict access by screening data packets against defined access
rules. They make access control decisions based on IP address and protocol. They also
"inspect" the session data to assure the integrity of the connection and to adapt to dynamic
protocols. These firewalls generally provide the best speed and transparency; however, they
may lack the granular application level access control or caching that some proxies support.
Firewalls, of one type or another, have become an integral part of standard security solutions
for enterprises.

15.1.2 About the ZyXEL Device Firewall

The ZyXEL Device firewall is a stateful inspection firewall and is designed to protect against
Denial of Service attacks when activated. The ZyXEL Device's purpose is to allow a private
Local Area Network (LAN) to be securely connected to the Internet. The ZyXEL Device can
be used to prevent theft, destruction and modification of data, as well as log events, which may
be important to the security of your network.

The ZyXEL Device is installed between the LAN and a WiMAX base station connecting to
the Internet. This allows it to act as a secure gateway for all data passing between the Internet
and the LAN.

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The ZyXEL Device has one Ethernet (LAN) port. The LAN (Local Area Network) port
attaches to a network of computers, which needs security from the outside world. These
computers will have access to Internet services such as e-mail, FTP and the World Wide Web.
However, "inbound access# is not allowed (by default) unless the remote host is authorized to
use a specific service.

15.1.3 Guidelines For Enhancing Security With Your Firewall

1 Change the default password via web configurator.
2 Think about access control before you connect to the network in any way.
3 Limit who can access your router.
4 Don't enable any local service (such as telnet or FTP) that you don't use. Any enabled

service could present a potential security risk. A determined hacker might be able to find
creative ways to misuse the enabled services to access the firewall or the network.

5 For local services that are enabled, protect against misuse. Protect by configuring the

services to communicate only with specific peers, and protect by configuring rules to
block packets for the services at specific interfaces.

6 Protect against IP spoofing by making sure the firewall is active.
7 Keep the firewall in a secured (locked) room.

15.1.4 The Firewall, NAT and Remote Management

Figure 113 Firewall Rule Directions

15.1.4.1 LAN-to-WAN rules

LAN-to-WAN rules are local network to Internet firewall rules. The default is to forward all
traffic from your local network to the Internet.

You can block certain LAN-to-WAN traffic in the Services screen (click the Services tab). All
services displayed in the Blocked Services list box are LAN-to-WAN firewall rules that block
those services originating from the LAN.

Blocked LAN-to-WAN packets are considered alerts. Alerts are "higher priority logs# that
include system errors, attacks and attempted access to blocked web sites. Alerts appear in red
in the View Log screen. You may choose to have alerts e-mailed immediately in the Log
Settings screen.

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LAN-to-LAN/ZyXEL Device means the LAN to the ZyXEL Device LAN interface. This is
always allowed, as this is how you manage the ZyXEL Device from your local computer.

15.1.4.2 WAN-to-LAN rules

WAN-to-LAN rules are Internet to your local network firewall rules. The default is to block
all traffic from the Internet to your local network.

How can you forward certain WAN to LAN traffic? You may allow traffic originating from the
WAN to be forwarded to the LAN by:

Configuring NAT port forwarding rules.
Configuring One-to-One and Many-One-to-One NAT mapping rules in the SMT NAT

menus.

Configuring WAN or LAN & WAN access for services in the Remote Management

screens or SMT menus. When you allow remote management from the WAN, you are
actually configuring WAN-to-WAN/ZyXEL Device firewall rules. WAN-to-WAN/ZyXEL
Device firewall rules are Internet to the ZyXEL Device WAN interface firewall rules. The
default is to block all such traffic. When you decide what WAN-to-LAN packets to log,
you are in fact deciding what WAN-to-LAN and WAN-to-WAN/ZyXEL Device packets
to log.

Forwarded WAN-to-LAN packets are not considered alerts.

Chapter 15Firewall

15.2 Triangle Route

When the firewall is on, your ZyXEL Device acts as a secure gateway between your LAN and
the Internet. In an ideal network topology, all incoming and outgoing network traffic passes
through the ZyXEL Device to protect your LAN against attacks.

Figure 114 Ideal Firewall Setup

15.2.1 The "Triangle Route# Problem

A traffic route is a path for sending or receiving data packets between two Ethernet devices.
You may have more than one connection to the Internet (through one or more ISPs). If an
alternate gateway is on the LAN (and its IP address is in the same subnet as the ZyXEL
Device!s LAN IP address), the "triangle route# (also called asymmetrical route) problem may
occur. The steps below describe the "triangle route# problem.

1 A computer on the LAN initiates a connection by sending out a SYN packet to a

receiving server on the WAN.

2 The ZyXEL Device reroutes the SYN packet through Gateway A on the LAN to the

WAN.

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3 The reply from the WAN goes directly to the computer on the LAN without going

through the ZyXEL Device.

As a result, the ZyXEL Device resets the connection, as the connection has not been
acknowledged.

Figure 115 !Triangle Route" Problem

15.2.2 Solving the "Triangle Route# Problem

If you have the ZyXEL Device allow triangle route sessions, traffic from the WAN can go
directly to a LAN computer without passing through the ZyXEL Device and its firewall
protection.

Another solution is to use IP alias. IP alias allows you to partition your network into logical
sections over the same Ethernet interface. Your ZyXEL Device supports up to three logical
LAN interfaces with the ZyXEL Device being the gateway for each logical network.

It!s like having multiple LAN networks that actually use the same physical cables and ports.
By putting your LAN and Gateway A in different subnets, all returning network traffic must
pass through the ZyXEL Device to your LAN. The following steps describe such a scenario.

1 A computer on the LAN initiates a connection by sending a SYN packet to a receiving

server on the WAN.

2 The ZyXEL Devicereroutes the packet to Gateway A, which is in Subnet 2.
3 The reply from the WAN goes to the ZyXEL Device.
4 The ZyXEL Device then sends it to the computer on the LAN in Subnet 1.

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Figure 116 IP Alias

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