Multitech SocketModem MT2456SMI-22 Instruction Manual

SocketModemÔ
Embedded Modem
MT2456SMI–22
Serial Interface
Developer’s Guide

Copyright
Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 2
SocketModemÔ
MT2456SMI–22
Developer’s Guide
PN S000281A, Version A
Copyright
This publication may not be reproduced, in whole or in part, without prior expressed written permission from Multi-
Tech Systems, Inc. All rights reserved.
Copyright © 2003, by Multi-Tech Systems, Inc.
Multi-Tech Systems, Inc. makes no representations or warranties with respect to the contents hereof and specifically
disclaims any implied warranties of merchantability or fitness for any particular purpose. Furthermore, Multi-Tech
Systems, Inc. reserves the right to revise this publication and to make changes from time to time in the content hereof
without obligation of Multi-Tech Systems, Inc. to notify any person or organization of such revisions or changes.
Revisions
Revision Level Date Description
A03/20/03 Initial release.
Trademarks
Multi-Tech Systems, Inc. trademarks include the SocketModem and the Multi-Tech logo.
Microsoft, Windows, Windows 95, Windows NT, and Windows 2000 are registered trademarks or trademarks of
Microsoft Corporation in the United States and/or other countries.
Patents
This device covered by one or more of the following patents: 6,031,867; 6,012,113; 6,009,082; 5,905,794; 5,864,560;
5,815,567; 5,815,503; 5,812,534; 5,809,068; 5,790,532; 5,764,628; 5,764,627; 5,754,589; 5,724,356; 5,673,268;
5,673,257; 5,644,594; 5,628,030; 5,619,508; 5,617,423; 5,600,649; 5,592,586; 5,577,041; 5,574,725; 5,559,793;
5,546,448; 5,546,395; 5,535,204; 5,500,859; 5,471,470; 5,463,616; 5,453,986; 5,452,289; 5,450,425; 5,355,365;
5,309,562; 5,301,274
Other Patents Pending
World Headquarters
Multi-Tech Systems, Inc.
2205 Woodale Drive
Mounds View, Minnesota 55112
Phone: [phone] or 800-328-9717
Fax: [phone]
Technical Support
Country By Email By Phone
France: [e-mail] (33) 1-64 61 09 81
India: [e-mail] 91 (124) 6340778
U.K.: [e-mail] (44) 118 959 7774
U.S. and Canada: [e-mail] [phone]
Rest of the World: [e-mail] [phone]
Internet Address: http://www.multitech.com

Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 3
Contents
Chapter 1 – Product Description and Specifications .................................................................................................4
Product Description....................................................................................................................................................4
Technical Specifications.............................................................................................................................................5
Chapter 2 – Mechanical Specifications........................................................................................................................6
Physical Dimensions ..................................................................................................................................................6
Pin Configurations......................................................................................................................................................7
Chapter 3 – Electrical Characteristics .........................................................................................................................9
Chapter 4 - V.22bis Commands, S-Registers, and Result Codes ............................................................................10
V.22bis Generic Modem Control Commands...........................................................................................................12
V.22bis DTE/DCE-Modem Interface commands......................................................................................................15
V.22bis Call Control Commands ..............................................................................................................................21
V.22bis Modulation Control Commands...................................................................................................................27
V.22bis Error Control and Data Compression Commands.......................................................................................29
V.22bis Synchronous Access Mode Commands .....................................................................................................31
V.22bis FastConnect Command ..............................................................................................................................33
V.22bis Line Side Device Commands ......................................................................................................................34
V.22bis S-Parameters ..............................................................................................................................................35
V.22bis Result Codes...............................................................................................................................................45
Appendix A – Test/Demo Card Information...............................................................................................................47
Block Diagram..........................................................................................................................................................47
Appendix B - Product Approvals, Compliance, and Layout Considerations .........................................................48
Product Safety and EMC Approvals.........................................................................................................................48
Regulatory Design Considerations...........................................................................................................................49
SocketModem Placement ........................................................................................................................................51
Compliance ..............................................................................................................................................................52
Index .............................................................................................................................................................................57

Chapter 1 – Product Description and Specifications
Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 4
Chapter 1 – Product Description and
Specifications
The Multi-Tech SocketModem supports analog data modem operation with V.22bis Fast Connect, V.42bis data
compression, and V.80 synchronous access mode. The SocketModem is a space-efficient (1" × 2.5"), embedded
modem that is ready-to-integrate into your applications; therefore, dramatically reducing development time and
costs for system designers. The SocketModem also complies with telecom requirements globally and can be
shipped worldwide.
This guide provides the information needed to effectively integrate the SocketModem into your equipment. It also
includes the AT commands for the configuration and control of a data modem and the result codes that the
modem issues in response to the commands.
Product Description
The MT2456SMI SocketModem is a standard 64-pin modem used for integrating data communications. It is a
single-port 5V or 3.3V modem that integrates a modem controller, DSP, and DAA in a 1" x 2.5" form factor and
communicates to a host controller via an asynchronous serial interface.
A SocketModem kit is available. It includes one development board with an RS-232 DB-25 connector, wall power
adapter, RJ-11 jack, and RS-232 cable.

Chapter 1 – Product Description and Specifications
Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 5
Technical Specifications
The SocketModem meets the following specifications:
Client-to-Server Data Rates V.22 bis
Client-to-Client Data Rates 2400, 1200, 0-300 bps
Data Format Serial, asynchronous
Modem Compatibility V.22bis, V.22; Bell 212A and 103/113; ITU-T V.21 & V.23
Error Correction ITU-T V.42 (LAP-M or MNP 2–4)
Data Compression ITU-T V.42bis
Speed Conversion Serial port data rates adjustable to 300, 1200, 2400, 4800, 9600, 19,200, 38,400,
57,600, and 115,200
Modes of Operation Full duplex over dial-up lines; data mode, command mode, and online command
mode
Flow Control XON/XOFF (software), RTS/CTS (hardware)
Command Buffer 50 characters
Transmit Level –12 dBm (varies by country setting)
Frequency Stability ±0.01%
Receiver Sensitivity –43 dBm under worst-case conditions
Interface Serial ITU-T V.24 logical interface
Diagnostics Local analog loop
Weight 0.02 Kg. (0.04 lb.)
Dimensions 1.045" × 2.541" × 0.680" (2.7 x 6.5 x 1.8 cm)
Power Consumption Typical: 70 mA (.235 W @ 3.3V DC); Maximum: 80 mA (.264 W @ 3.6V DC)
Operating Voltage Typical: 3.3V DC +/- 5%; Absolute Maximum Supply Voltage: 3.7 V DC
Operational Temperature 0 to +70° C ambient under closed conditions; humidity range 20% to 90% (non-
condensing)
Storage Temperature -10° to +85° C
Intelligent Features TIA-602 command compatible
V.22bis fast connect
Supports V.80
Supports Fast POS 9600
Line polarity reversal detection
Line current loss detection
Line-in-use detection during on-hook operation
Extension pickup detection
Call waiting detection
Caller ID (US configuration only)
DTMF detection
autodial, redial
pulse or tone dial
auto answer
call status display

Chapter 2 -Mechanical Specifications
Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 6
Chapter 2 – Mechanical Specifications
Physical Dimensions
Figure 2–1. Maximum Component Height

Chapter 2 -Mechanical Specifications
Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 7
Pin Configurations
The MT2456SMI SocketModem with a serial interface use a 16-pin interface to provide an on-board DAA with tip
and ring connections, audio circuit for call-progress monitoring and serial interface via logic level signals.
Figure 2–2. Serial SocketModem Pins
Pin Descriptions
Pin
#
Signal
Name
I/O
Type Description
1 Tip I/O Tip Signal from Telco. Tip connection to the phone line (RJ11 Pin 3).
SocketModem is Tip/Ring is polarity insensitive.
2 Ring I/O Ring Signal from Telco. Ring connection to the phone line (RJ11 Pin 4).
SocketModem is Tip/Ring is polarity insensitive.
24 –RESET I Modem Reset (with weak pull-up). The active low –RESET input resets the
SocketModem logic and returns the AT command set to the original factory
default values or to "stored values" in NVRAM. –RESET is tied to VCC
through a 250 ms time constant circuit for "Power-on-Reset" functionality. The
modem is ready to accept commands within 6.5 seconds of power-on or reset.
Reset must be asserted for a minimum of 300 ns.
26 DGND Ground.
29 DCDIND DCD LED Indicator.
30 RXIND RXD LED Indicator.
31 DTRIND DTR LED Indicator.
32 TXIND TXD LED Indicator.
33 –RTS I Request to Send. RTS signal is used for hardware flow control.
34 –RXD O Received Data. Used to send data received from the telephone line and also
modem responses to the DTE. Modem response take priority over incoming
data. When no data is transmitted, the signal is held in mark condition.
35 –TXD I Transmit Data. The DTE uses this line to send data to the modem for
transmission over the telephone line or to transmit commands to the modem.
The DTE should hold this circuit in the mark state when no data is being
transmitted or during intervals between characters.

Chapter 2 -Mechanical Specifications
Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 8
36 –RI O Ring Indicate. –RI output ON (low) indicates the presence of an ON segment
of a ring signal on the telephone line. The modem will not go off-hook when –
RI is active; the modem waits for –RI to go inactive before going off-hook.
37 –DSR O Data Set Ready. -DSR indicates modem status to the DTE. –DSR OFF
(high) indicates that the DTE is to disregard all signals appearing on the
interchange circuits except Ring Indicator (–RI). It reflects the status of the
local data set, and does not indicate an actual link with any remote data
equipment.
38 –CTS O Clear To Send. –CTS is controlled by the modem to indicate whether or not
the modem is ready to transmit data. –CTS ON, indicates to the DTE that
signals presented on TXD will be transmitted to the telephone line. –CTS OFF
indicates to the DTE that it should not transfer data across the interface on
TXD.
39 –DCD O Data Carrier Detect. –DCD output is ON (low) when a carrier is detected on
the telephone line or OFF (high) when carrier is not detected.
40 –DTR I Data Terminal Ready (Active Low). The –DTR input is turned ON (low) by
the DTE when the DTE is ready to transmit or receive data. –DTR ON
prepares the modem to be connected to the telephone line, and, once
connected, maintains the connection. –DTR OFF places the modem in the
disconnect state.
41 DGND Ground.
61 VCC 3.3V DC Power.
63 AGND Analog Ground. Analog ground is tied common with DGND on the
SocketModem. To minimize potential ground noise issues, connect audio
circuit return to AGND.
64 SPKR Speaker Output. SPKR is a single ended-output. SPKR is tied directly to the
CODEC. One side of a differential AC output coupled through a 6.8K ohm
resistor and capacitor.
The call progress speaker interface signal is:
Digital speaker output (DSPKOUT); output
DSPKOUT is a square wave output in data mode used for call progress or
carrier monitoring. This output can be optionally connected to a low-cost on-
board speaker, e.g., a sounducer, or to an analog speaker circuit.

Chapter 3 -Electrical Characteristics
Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 9
Chapter 3 – Electrical Characteristics
3.3V and 5V Serial SocketModem
3.3V DC Characteristics (TA = 0°C to 70°C; VDD = 3.3 V ± 0.3 V) VDDMAX = 3.6 V
5V DC Characteristics (TA = 0°C to 50°C; VDD = 5 V ± 0.25 V) VDDMAX = 5.25 V
Inputs Input High Input Low
–DTR (40), –TXD (35), –RTS (33), –RESET (24) Min 2.0 V Max 0.8 V
Outputs Output High Output Low
–DCD (39), –CTS (38), –DSR (37), –RI (36), –RXD (34)
2mA, Z INT = 120 Ω
Digital Input Capacitance
Min 2.4 V Max 0.4 V
50pF
Handling Precautions
All electronic devices should be handled with certain precautions to avoid damage due to the accumulation of
static charge. Although input protection circuitry has been incorporated into the devices to minimize the effect of
this static buildup, proper precautions should be taken to avoid exposure to electrostatic discharge during
handling and mounting.

Chapter 4 - V.22bis Commands
Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 10
Chapter 4 - V.22bis Commands, S-
Registers, and Result Codes
The V.22bis Commands are covered in the following order in this chapter:
Generic Modem Control Commands
Z Soft Reset and Restore Profile
+VCID Caller ID
+VRID Report Retrieved Called ID
\N Operating Mode - Error Correction
I Identification
+GCI Country of Installation
&F Restore Factory Configuration (Profile)
&T Local Analog Loopback Test
** Load to Internal RAM
DTE/DCE Commands
E Echo
Q Quiet Result Codes
V Result Code Form
W Connect Message Control
X Extended Result Codes (& Call Progress Information)
&C RLSD Option
&D DTR Option
&K Flow Control
&R RTS/CTS Option
\G Modem-to-Modem Flow Control (XON/XOFF)
+IFC DTE-Modem Local Flow Control
+IBC In Band Commands
Call Control Commands
DDial
T Set Tone Dial (Default)
P Set Pulse Dial
A Answer
H Disconnect (Hang Up)
O Return to On-line Data Mode
L Monitor Speaker Volume
M Monitor Speaker Mode Control
&G Select Guard Tone
&P Select Pulse Dial Make/Break Ratio
&V Display Current Configuration and Stored Profiles
%L Report Line Signal Level
%Q Report Line Signal Quality
*B Display Blacklisted Numbers
*D Display Delayed Numbers
-STE Set Telephony Extension
+PCW Call Waiting Enable
+VDR Distinctive Ring
Modulation Control Commands
+MS Modulation Selection
%E Enable/Disable Line Quality Monitor
BITU-TorBell