G l o b a l Vo i c e I S O m o d e m - E V B
Evaluation Board for the Si2494/39/38/37/36/35/29/19/18/17
ISOModem
Description
The Global Voice ISOmodem EVB evaluation board
provides the system designer with an easy way of
evaluating the ISOmodem
. The Voice ISOmodem EVB
consists of a motherboard with a complete removable
daughter card
The Voice ISOmodem is a complete controller based
modem chipset with an integrated and programmable
direct access arrangement (DAA) that meets the global
telephone line requirements. It is available in a 24-pin or
38-pin system side device and a 16-pin line side device.
The hardware versions at the time of publication are:
Voice Mother Board Si24xxVMB Rev 2.0
Modem Daughter Card Si24xx2G-DC Rev 2.0
Modem Daughter Card Si24xx2G-QFN38-DC Rev
1.0
The voice daughter card is populated with the correct
ISOmodem system side chip (Si2494/39/38/37/36/35/
29/19/18/17) and the correct line side DAA chip, the
Si3018 to suit the voice applications.
Features
This evaluation board includes the following:
Socketed module with the modem chipset
USB or asynch RS232 Serial Interface
RJ11 connection to the phone line
Onboard relay-excludable RJ11 connection
RS232 and USB interface to the PC
Direct access to the ISOmodem signals for
embedded system evaluation
Power from a provided 8.5–13.5 V dc power supply
or from the USB port
Handset connector (J1)
Onboard hookswitch
External hookswitch connector
Jumper matrix that allows any handset wiring
scheme to work with this board
Onboard speakerphone microphone
RCA jack connector to an optional off-board
speakerphone electret microphone
Selectable and adjustable electret power supplies for
both handset and speakerphone microphones
Onboard 300 mW audio power amplifier (into a 4
load) for driving either onboard or external speaker.
Onboard voice coil driven loudspeaker for call
monitoring
LED display of all RS232 signals
The ISOmodem eliminates the need for a separate DSP
data pump, modem controller, memories, codec,
isolation transformers, relays, opto-isolators and a 3-4
wire hybrid. The ISOmodem is ideal for embedded
modem and voice applications due to its small board
area, controller based architecture, low power
consumption and global compliance.
An onboard rectifier, filter, and voltage regulator allow
the power input to be 7.5–13 V ac or dc (either polarity)
supplied through a screw terminal (J8) or a standard
2 mm power jack (J9). Alternatively, power can be
supplied through the USB interface (whether the USB or
RS232 interface is used).
The Power Source Selection in automatic, while the
signaling port is selected by a jumper (JP23).
The evaluation board audio power amplifier can drive
an external speaker for either call progress monitoring
or speakerphone function. A small onboard speaker,
suitable for call progress monitoring, is installed.
Please note that fax modem versions listed in the title
require a software driver in order to implement fax send/
receive functionality. The driver must be compliant with
the Silicon Labs ISOmodem and with applicable ITU-T
standards (e.g., T.30, T.31, T.4 and T.6) Contact Silicon
Labs for details.
Rev. 0.4 8/11
Copyright © 2011 by Silicon Laboratories
Si24xxVMB-EVB
Si2494/39/38/37/36/35/29/19/18/17FT18-EVB
Functional Block Diagram
As shown in Figure 1, the daughter card is a plug-in component with the complete modem, while the rest of the
motherboard provides selectable serial RS232 or USB links, the sound subsystem, and power regulation and
distribution.
I/O LED
Display
ISOmodem
Daughter
Card
Call
Progress
Audio
PCM
Sound
Subsystem
USB/RS232
Connectors
J11/J10
Interface
Logic
Pwr
Amp
Si2494/
Si2438
Series
ISOmodem
Ext.
Speaker
JP11
Handset
RJ10
EXT.
Microphone
J2
Si3000
Power
Connectors
Regulation
&
Switching
Silicon Labs
SI3018 DAA
LED Status
Display
On Board
Hook Switch
Exclusion
Relay
RJ 11
Telephone
Connector
RJ 11
Telephone
Connector
Loudspeaker
Figure 1. Functional Block Diagram
The voice ISOmodem EVB provides a sound system consisting of the Si3000 codec along with a handset RJ10
connector as well as onboard microphone and loudspeaker with options for these devices to be placed off-board.
The bias voltages for both the onboard microphone and the handset microphone can modified and alternate
sources used.
This allows the board to be used as a telephone or as a speakerphone as is, or to be integrated into the customer's
system.
The evaluation board can drive an external speaker or a small onboard speaker. For speaker-phone applications it
is recommended that an off board loudspeaker be used.
An onboard rectifier, filter and voltage regulator allow the power input to be 8.5 to 13.5 V peak ac or dc of either
polarity supplied through screw terminals (J8) or a standard 2 mm power jack (J9). Alternatively the power can be
supplied through the USB interface. Automatic switching is provided for the power, but not for the data interface.
That data interface is selected by JP23.
2
Rev. 0.4
Si2494/39/38/37/36/35/29/19/18/17FT18-EVB
1. Global Voice ISOmodem EVB
The evaluation board is shown in Figure 2. Note the socketed daughter card with the modem chipset on the bottom
right of the board.
Figure 2. Global Voice ISOmodem Evaluation Board
The ISOmodem chip requires software driver in order to perform either FAX or sound functionality. Contact Silicon
Labs for details. “AN244: Si2438/37/36/35/29/19/18/17 Fax Modem Designer’s Guide” and “AN93: Si2494/93/57/
39/34/15/04 Data Modem Designer’s Guide” are useful for driver development.
The Global Voice ISOmodem EVB provides an RJ11 jack for interfacing to the phone line and the USB or serial
ports can interface to a PC or a host CPU. This allows the board to operate as a class 1 fax modem for an
evaluation or as a global voice and data modem (depending on the specific ISOmodem used).
A handset, microphone and speaker can also be attached to demonstrate the sound features, which may include
TAM and speaker-phone operations, depending on the specific ISOmodem chip used. Table 1 lists which
ISOmodem chips have these features. A software driver or application is required to perform these data and sound
operations. The included UltraCOM application can demonstrate the sound features of the ISOmodem and
provides a tool to aid development.
Rev. 0.4
3
Si2494/39/38/37/36/35/29/19/18/17FT18-EVB
2. Daughter Cards
There are two types of daughter cards available for this EVB. One supports the TSSOP version of the system side
chip, and the other supports the QFN38 version of the system side.
An example of the TSSOP version of the daughter card is shown in Figure 3. It has the ISOmodem system-side
chip as well as the Si3018 DAA chip. The left side of the board contains the system side while the right side
contains the DAA chip along with the few interface parts needed to connect tot a telephone line.
Figure 3. Daughter Card
Although this card is provided as part of the global voice EVB, it can also be directly connected to an embedded
system using TTL logic.
When run by a software driver the chipset on this daughter card is capable of making fax calls, telephone calls with
a handset, data calls and both. TAM and speaker-phone operations. Table 1 lists the various ISOmodem chips and
their features.
Table 1. ISOModem Features
Part Number
Si2417
Si2418
Si2419
Si2429
Si2435
Si2436
Si2437
Si2438
Si2439
Si2494
Fax
≤V.17
≤V.17
≤V.17
≤
V.29
≤V.34
≤V.34
≤V.34
≤V.34
—
—
Data
—
—
≤V.32bis
—
—
—
≤V.34
≤V.34
≤V.34
≤V.92
Handset
TAM
—
—
—
—
Speaker
Phone
—
—
—
—
4
Rev. 0.4
Si2494/39/38/37/36/35/29/19/18/17FT18-EVB
3. Setup and Evaluation
This section explains how to set up the Voice ISOmodem EVB for evaluation as an RS-232 or USB interface.
Jumper settings and system interconnections are given, as well as the use of an demonstration and test
application provided called UltraCOM.
See the following documents for additional technical details
Si2494/39/38/37/36/35/29/19/18/17 data sheets
“AN244: Fax Modem Designer's Guide"
“AN93: Data Modem Designer’s Guide”
Diagrams and tables are provided here that define the operation of all the jumpers, settings and connectors, as
well as their default states.
A typical global voice EVB as it arrives from the factory can be connected into a system by using only four cables.
Figure 4. Global Voice ISOmodem EVB Connection
The UltraCOM application provided on the included CD can be used to demonstrate:
Telephone Operation.
Speakerphone Operation
Telephone answering machine operation.
Fax Operation can be demonstrated but requires a fax driver application.
Rev. 0.4
5
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
