1. Home
    2. /
  2. Manuals
    3. /
  3. TRENDnet
    4. /
  4. TVP-221H
    5. /
  5. 4
Page 16 / 100 Scroll up to view Page 11 - 15
3
Chapter 3
TVP-221H Telephony
Concepts
The TVP-221H enables the transmission of voice and fax traffic over any IP network by
digitizing voice and fax signals, encapsulating the information within IP packets, and then
sending the packets across the IP network
3.1
How the TVP-221H Operates
1.
The TIM inside the TVP-221H digitizes analog voice signals at 8 Kbps.
2.
TVP-221H system software handles the:
•
Capture of telephone number presented as DTMF tones.
•
Mapping the telephone number to the IP address of remote VoIP
Gateway.
•
Setting up calls with remote TVP-221Hs utilizing H.323 call control
protocol.
•
Digitizing, compressing and encapsulating the voice into IP packets and
transmission of the IP packets onto the Ethernet LAN.
3.
A router attached to the LAN forwards the IP packets across the WAN, where
they will be received by another VoIP Gateway at the remote.
4.
The process is reversed at the remote VoIP Gateway.
3.2
ATPM
To allow you to easily dial a telephone or fax on the network, the TVP-221H
maps a series of dialed digits to the IP address of the remote TVP-221H whose
phone or fax you are calling. This mapping information is contained in a database
inside each TVP-221H called the dial plan.
Based on the dial plan, the Address Translation and Parsing Manager (ATPM)
inside the TVP-221H maps telephony numbers to IP addresses of remote VoIP
Gateways. The ATPM collects telephone number dialed by users, decides whether
the dial string is part of the dial plan and, if it is, maps it to a remote TVP-221H /
TVP-224HR. When the call is set up to the destination, a sub-string of the original
dial string will be sent along to the remote VoIP Gateway.
3.3
Destination
The destination is where a call is terminated. Typically, for inbound calls from the
IP network, the TVP-221H terminals the call at one of the telephony ports. The
16
Page 17 / 100
TVP-221H User’s Guide
17
destination for the call is the telephony port where the call terminated. For calls
initiated from telephony ports, the TVP-221H forwards the call to a remote TVP-
221H/TVP-221H via IP network, and the remote TVP-221H/TVP-221H
terminates the call. The destination of the call is the remote TVP-221H/TVP-
224HR.
3.4
Hunt Group
Instead of directly mapping a phone number to a destination, the ATPM first maps
the phone number to a group of destinations known as a Hunt Group. A hunt
group is a group of destinations that are equivalent.
For example, the customer
support group of a company might have 20 people who can handle support
calls. Access to customer support is through a single phone number but the
next available support person is actually connected upon each incoming
call. These 20 phones would be configured as a hunt group. A hunt group
consists of a phone number and a list of destinations (members of the
group).
When
an incoming phone number matches the phone number of the hunt
group, the TVP-221H attempts to terminate the call at each of the destinations in
the hunt group, one at a time until a call is successfully completed.
Every destination that can be reached by dialing a phone number is a member of at
least one hunt group. When an address is presented to ATPM for lookup, the
output is a hunt group ID number. As a second step, the hunt group ID is
presented to ATPM to get the list of members. To effectively bypass the hunt
group feature, simply assign a unique hunt group number to a single destination.
In effect, the Hunt Group will just have this one member.
3.5
Dial Plan
The dial plan is a database inside the TVP-221H that allows the ATPM to map
telephone numbers dialed to IP addresses of remote VoIP Gateways. The dial plan
consists of three tables; destination table, hunt group table and the address table.
Users need to setup these tables in order for the TVP-221H to process calls to
remote VoIP Gateways.
3.51
Address Table
The address table maps a phone number to a hunt group. The table contains entries
that specify the following information:
•
Telephone number
•
The hunt group the phone number maps to.
•
The minimum number of digits to collect before the ATPM starts address
lookup.
•
The maximum number of digits the ATPM collects before it considers the
dial string is complete.
•
Number of digits forwarded to the destination.
Page 18 / 100
TVP-221H User’s Guide
18
•
Address table sample:
Address
Entry
Hunt
Grp_Id
Min.
Digits
Max. Digits
Prefix
strip
Prefix
Address
201
3
3
3
3
None
301
4
3
3
3
None
8
1
3
3
0
None
0
1
1
1
0
None
20
11
5
5
2
None
3.52
Hunt Group Table
The hunt group table maps a hunt group to a list of destinations. Hunt group
sample
Hunt Group ID
Hunt Type
# of Dest ID(s)
Dest. ID(s)
1
2
1
1
3
2
1
3
4
2
1
4
11
2
1
11
3.53
Destination Table
The destination table maps a destination to a telephony port or the IP address of a
remote TVP-221H.
Destination table sample
Dest ID
Mode
Destination
1
Local
Port = 0
3
Local
Port = 2
4
Local
Port = 3
11
H.323
Dest = 192.168.0.55/1720 TCP
3.6
DTMF Relay
Voice from PSTN is compressed by the TVP-221H before it is sent across the IP
network and then decompressed by the destination VoIP gateway. The voice
codecs supported by the TVP-221H are designed for ideally compressing and
decompressing human voice. If the compression / decompression process is
performed on DTMF tone which needs to be conveyed across IP network,
distortion might be too significant to be
cognizable on the receiving end. To
overcome the shortcoming that the voice codecs may have encoding DTMF tone,
the TVP-221H encodes DTMF tone into special packets. The packets are then sent
to the destination VoIP Gateway via a separate IP connection. The destination
VoIP Gateway decodes the packets, generates the DTMF tone, and then sends the
Page 19 / 100
TVP-221H User’s Guide
19
tone to the PSTN. This method in which the TVP-221H handles DTMF tone is so
called DTMF relay.
The TVP-221H handles DTMF relay per H.323 specifications. Certain third party
VoIP devices may handle DTMF relay per IMTC standard. For the TVP-221H to
interoperate with those VoIP devices, users need to specify which remote VoIP
devices uses IMTC conforming DTMF relay technique. Refer to CLI command
Error! Reference source not found. on Chapter 8 for detailed information on how
to select DTMF relay mode.
3.7
Voice Codecs
Voice codecs supported by the TVP-221H include G.711, G.723.1 5.3kbps,
G.723.1 6.3kbps and G.729 AB. When setting up a call, two VoIP Gateways
automatically negotiate with each other until an agreement on codec is
determined.
Page 20 / 100
TVP-221H User’s Guide
4
Chapter 4
Configuring TVP-221H from
a Web Browser
This chapter explains procedures for configuring the TVP-221H from a web browser.
4.1
HTTP setting mode
This section describes the processes for setting up the VoIP Gateway once it has been
installed.
Java enabled browsers including Microsoft Explorer version 4 or higher, or
Navigator version 4.5 or higher can be used in this section to view and change
parameters.
PC Setup
In order to configure the TVP-221H, the Terminal PC needs to have TCP/IP protocol
and a compatible IP Address.
1.
Connect the TVP-221H to the network with a RJ-45 UTP cable. Power it on.
2.
To configure a PC under Windows 95/98, select the
Network Neighborhood
icon
on the desktop, then select
Properties
.
You will see a screen like below:
3. If a line like the one highlighted ("TCP/IP -> Network Card”) is not listed , select
A
dd-Protocol-Microsoft-TCP/IP-OK
to add it.
4. Select
Properties
for the “TCP / IP -> Network card” entry. You will see a screen
like the following:
20

Rate

3.5 / 5 based on 2 votes.

Popular TRENDnet Models

Famous Router IPs
Famous Router Companies
Bookmark Our Site

Press Ctrl + D to add this site to your favorites!

Share
Top