Linksys ATA

Administrator Guide

Document Version 3.1

Chapter 2

Getting Started

Linksys Analog Telephone Adapters (ATAs)

WRT54GP2

The WRP54GP2 provides an ATA with two FXS ports and a Wireless-G multiport IP router (see

Figure 1-13

). The WRP54GP2 provides connectivity to an analog telephone as well as Internet

connectivity to a LAN with a built-in four-port switch. The IP router provides QoS support, an integrated

firewall and VPN pass-through, and full routing with DHCP and NAT.

Figure 1-13

WRT54GP2

The following tables describe the LEDS on the front panel and the ports on the back panel of the device.

Table 1-22

WRT54G P2 Front Panel

LED

Function

Power

Steady green indicates that the power supply is connected and the device is

functioning.

WLAN

Steady green indicates an active connection to the network. Flashing

indicates traffic.

Ethernet 1-3

Steady green indicates an active connection to the network. Flashing

indicates traffic.

Phone 1/2

Steady green when telephone or fax machine has an active or registered

connection to the ITSP through the Phone port. Flashing indicates phone is

in use or off hook.

Internet

Steady green indicates active connection. Flashing indicates traffic.

Table 1-23

WRTP54G Back Panel

Port

Function

Internet

Connect to the broadband (cable/DSL) modem using an Ethernet cable.

Phone 1/2

Connect to an analog telephone or fax machine using an RJ-11 cable.

Linksys ATA

Administrator Guide

Document Version 3.1

Chapter 2

Getting Started

Establishing Connectivity

Establishing Connectivity

This section describes how to connect the Linksys ATA hardware. It includes the following topics:

•

Bandwidth Requirements, page 2-14

•

Making the Physical Connections, page 2-15

Bandwidth Requirements

Depending on how you have your IP phones configured, each call requires 55 to 110 kbps in each

direction. Therefore, using G.729 as the voice codec setting, and with an average business-grade

broadband Internet connection supporting 1.5 Mbps downstream and 384 kbps upstream, a total of seven

(7) simultaneous conversations can be reliably supported with adequate bandwidth available for file

downloads.

Linksys recommends using the Linksys ATA with QoS-capable networking equipment that can

prioritize the VoIP application traffic. QoS features are available on many Linksys data networking

switches and routers. A QoS-enabled router prioritizes the packets going upstream to the ISP.

Table 1-24

illustrates the bandwidth budget using different codecs.

This table is based on the following assumptions:

•

Bandwidth Calculated with No Silence Suppression

•

20 milliseconds of payload per RTP packet

Note

The use of silence suppression can reduce the average bandwidth budget by 30% or more.

For more information about bandwidth calculation, refer to the following websites:

Ethernet 1-3

Connect to local IP devices, such as PCs, using an Ethernet cable.

Power

Connect to the power supply.

Table 1-23

WRTP54G Back Panel

Port

Function

Table 1-24

Ethernet Bandwidth Budget for Off-Net VoIP Calling

Codec

Approximate bandwidth budget for each

side of conversation

2 calls

4 calls

6 calls

8 calls

G.711

110 kbps

220 kbps

440 kbps

660 kbps

880 kbps

G.726-40

87 kbps

174 kbps

348 kbps

522 kbps

696 kbps

G.726-32

79 kbps

158 kbps

316 kbps

474 kbps

632 kbps

G.726-24

71 kbps

142 kbps

284 kbps

426 kbps

568 kbps

G.726-16

63 kbps

126 kbps

252 kbps

378 kbps

504 kbps

G.729

55 kbps

110 kbps

220 kbps

330 kbps

440 kbps

Linksys ATA

Administrator Guide

Document Version 3.1

Chapter 2

Getting Started

Establishing Connectivity

Making the Physical Connections

Make sure that you have the following package contents:

•

Linksys phone adapter unit

•

Ethernet cable

•

RJ-11 phone cable (SPA3102/AG310 Only)

•

SPA Quickstart Guide

•

Volt power adapter

You also need the following:

•

One or two analog touchtone telephones (or fax Machine)

•

Access to an IP network via an Ethernet connection for WAN connectivity

•

Access to a PSTN network connection (SPA3102/AG310 only).

Perform the following steps to connect the Linksys ATA.

Step 1

Insert a standard RJ-45 Ethernet cable (included) into the LAN port and connect the other end to the

broadband router or modem.

Step 2

(Optional) For a Linksys ATA with more than one Ethernet port, you can connect the extra port to a PC

or other Ethernet device.

Step 3

Insert a standard RJ-11 telephone cable into the Phone 1 port.

Step 4

(Optional) For a Linksys ATA with more than one FXS port, you can connect the extra port to a second

analog telephone or a fax machine.

Note

Do not connect an RJ-11 telephone cable from the

Linksys ATA

to the wall jack to prevent any

chance of connection to the circuit switched Telco network.

Step 5

(SPA3102/AG310 only) Connect the RJ-11 phone cable (included) to the SPA3102 LINE port and to

your telephofne wall jack.

Step 6

Connect the included power adapter to the

Linksys ATA

power port, and then plug the power adapter

into an electrical outlet.

The power LED on the front panel will light up as soon as the device powers on.

Step 7

Power on the broadband modem or router.

Linksys ATA

Administrator Guide

Document Version 3.1

Chapter 2

Getting Started

Connecting the SPA8000

Connecting the SPA8000

The SPA8000 provides up to eight analog telephone connections, and is designed to function as a

network endpoint. This section describes the architecture and connectivy requirements of the SPA8000

and includes the following topics:

•

SPA8000 Architecture, page 2-16

•

Connectivity Requirements, page 2-17

SPA8000 Architecture

As shown in

Figure 1-14

, the SPA8000 consists of four hardware modules: one primary (Module 1) and

three secondary modules (Modules 2, 3, and 4).

Each module provides two FXS ports.

The primary

module supports Line 1 and Line 2, while the three secondary modules support Line 3-4, 5-6, and 7-8.

Figure 1-14

SPA8000 Internal Configuration

The four modules are interconnected through an internal IP network, configured automatically as a

single subnet, which by default is assigned the network address 192.168.0.0 with a subnet mask of

255.255.255.0. If a network conflict is detected from the device connected on the AUX port, the internal

network is automatically changed to 192.168.1.0.

The primary module is responsible for the management functions of the entire SPA8000, in addition to

handling calls on Line 1 and Line 2. These management functions include remote provisioning, firmware

upgrades, the administration web server, IVR functions, and SIP NOTIFY control messages (over Line

1 or 2). The IVR functions are accessed by connecting an analog telephone to Line 1 or Line 2.

Line 2

Line 1

Internet

IP Router (with

hairpinning) or

Broadband modem

ITSP

ISP

SPA8000

Line 4

Line 3

Line 6

Line 5

Line 8

Line 7

NAT/PAT

Internal DHCP

server

192.168.1.100

209.165.202.129

192.168.1.101

Ethernet

port

AUX

port

192.168.0.5

Administration

web server

Administrative

IVR (Line 1 or

Line 2)

Module 1

(primary)

Secondary

Module 2

192.168.0.1

8 FXS (RJ-

11/RJ-21 ) ports

Module 2

(secondary)

192.168.0.2

Module 3

(secondary)

192.168.0.3

Module 4

(secondary)

192.168.0.4

Linksys ATA

Administrator Guide

Document Version 3.1

Chapter 2

Getting Started

Connecting the SPA8000

The secondary modules (Module 2, 3, and 4) obtain configuration and firmware upgrades from the

primary module and are not managed directly. The primary module routes all the SIP and RTP traffic to

and from the secondary modules over the SPA8000 internal LAN, which also includes the AUX

maintenance port. The AUX maintenance port cannot be used to forward IP traffic. It is designed to

connect to the management functions on the SPA8000, such as the administration web server.

The secondary modules are assigned IP addresses by the DHCP server that runs on the primary module.

The primary module also performs Network Address Translation (NAT) and Port Address Translation

(PAT) on the IP addresses and ports used by the secondary modules, translating them into addresses and

port numbers that can be transmitted over the network connected to the Ethernet port.

For proper operation, the service provider should use an Outbound Proxy to forward all voice traffic

when the SPA8000 is located behind a router. If necessary, explicit port ranges can be specified for SIP

and RTP for each of the four modules.

When performing a firmware upgrade, either through remote provisioning or through the administration

web server, the SPA8000 downloads and upgrades the primary module first.

After successful upgrade

of the primary module, the three secondary modules update their firmware image directly from the

primary module.

The primary module is also connected through the Ethernet port to the external local area network, or

directly to the Internet. This modules receives its IP address through DHCP, or its address can be

statically assigned using the IVR or the administration web server. To access the IVR, connect an analog

telephone to the Phone 1 or Phone 2 port. To access the administration web server, connect a PC to the

AUX port.

Note

In the illustration, one fax machine is connected to each pair of ports to illustrate that only one T.38

connection is supported by each of the four pairs of RJ-11 ports. Up to four fax machines can be

connected to the SPA8000, but they must be distributed as shown.

The secondary modules (Line 3/4, 5/6, and 7/8) are assigned IP addresses by an internal DCHP server

provided by the SPA8000, and these addresses are not configurable.

Note

The SPA8000 is not designed to forward IP packets to devices connected to its AUX port and that

configuration is not supported.

Connectivity Requirements

The SPA8000 can be connected to a local router through its LAN port, or directly to the Internet. Each

phone connected to an RJ-11 (analog) port on the SPA8000 connects to other devices through SIP, which

is transmitted over the IP network.

In order to ensure connectivity between the devices connected to its FXS ports, the SPA8000 requires

the following functionality to be supplied on the network connected to its Ethernet port:

•

Connection to an IP router with hairpinning support

•

Connection to an outbound Proxy server

When a phone connected to a port on the SPA8000 communicates with another phone, it sends a SIP

packet onto the internal LAN, which is then forwarded to the external local area network or directly to

the Internet. The source address and source port on the original packet is assigned by the SPA8000