US Robotics USR3520 User manual

USRobotics®Courier® Modemulator™
User Guide & Technical Documentation
For the following products:
Modemulator & 3G M2M Cellular Gateway
USR3520, USR803520
Modemulator Upgrade Kit
USR3516-EMU
R24.0800.01
Rev 2.1 9/24/2015
For firmware version 1.0.02

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Contents
Contents ....................................................................................................................................2
About This Guide .........................................................................................................................7
Symbols Used In This User Guide...............................................................................................7
Important Safety Instructions ....................................................................................................8
General Recommendations For Use .........................................................................................8
Ambient Temperatures ..........................................................................................................8
Explosive Atmosphere ...........................................................................................................8
Driving ................................................................................................................................9
Medical Equipment ................................................................................................................9
ESD Notice ...........................................................................................................................9
Class A Device ......................................................................................................................9
Chapter 1: Features...................................................................................................................10
Introduction ..........................................................................................................................10
Overview of Main Features ................................................................................................... 10
Physical Features ................................................................................................................12
Mounting Instructions .......................................................................................................... 14
Chapter 2: Getting Started ......................................................................................................... 15
Verifying Modemulator Operation .............................................................................................15
Testing Modemulator Connectivity ............................................................................................ 18
System requirements ..........................................................................................................18
Set Up Cellular Connectivity .................................................................................................18
Configure Modemulator Dialing Directory ...............................................................................20
Making a Connection ........................................................................................................... 22
Chapter 3: Applications .............................................................................................................. 24

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Convert A Legacy Dial-up M2M System To Cellular ..................................................................... 24
Peer-to-Peer Operation ........................................................................................................24
Single-Ended Operation ....................................................................................................... 27
Maintain Compatibility with Dial-up Modems ..............................................................................30
Chapter 4: Command Reference..................................................................................................32
Using the AT Command Set ..................................................................................................... 32
Overview ........................................................................................................................... 32
General rules for using AT commands.................................................................................... 32
Modemulator Memory .............................................................................................................33
The Modemulator Base Unit.................................................................................................. 33
The Modemulator Expansion Card ......................................................................................... 33
AT Command Reference Guide.................................................................................................34
Basic Commands................................................................................................................. 34
Ampersand Commands ........................................................................................................ 45
Modemulator Commands ..................................................................................................... 50
S Registers......................................................................................................................... 60
Chapter 5: USR3520/USR803520 Technical Specifications .............................................................. 66
Physical ............................................................................................................................. 66
Serial Port Ratings .............................................................................................................. 66
Power ................................................................................................................................ 66
Radio Technology & Frequency Bands ....................................................................................68
Max. connectivity speeds .....................................................................................................68
GPS...................................................................................................................................69
Security ............................................................................................................................. 69
Minimum System Requirements ............................................................................................ 69
Command-line Interface ...................................................................................................... 69

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Graphical User Interface ...................................................................................................... 70
Environmental .................................................................................................................... 70
Enclosure Type ................................................................................................................... 70
Mounting ........................................................................................................................... 70
Package Dimensions/Weight................................................................................................. 70
Product Dimensions/Weight..................................................................................................70
Troubleshooting and FAQs ..........................................................................................................71
General................................................................................................................................. 71
What are displayable characters? .............................................................................................71
What are programmable characters? ........................................................................................71
What are dial modifier characters? ........................................................................................... 71
Can I use the SIM from my phone for Modemulator? ..................................................................71
What type of screwdriver do I need for installing a SIM or an expansion card?...............................72
What is peer-to-peer?............................................................................................................. 72
What is point-to-point? ........................................................................................................... 72
Can I enable both Caller ID Screening and Password Prompting? .................................................72
Can I enable both Caller ID Screening and Dialback Security?...................................................... 72
Why does an originating Modemulator report BUSY?...................................................................72
Can I connect to the IP address reported by the USR3520/USR803520? .......................................72
How do I configure a Modemulator for connection to the Vodafone UMTS network? ........................73
How do I restore the Modemulator expansion card to factory settings? .........................................73
Why do I need an M2M data plan with the Modemulator? ............................................................74
Can the Modemulator connect simultaneously to several remote sites? ......................................... 75
Can I use the Modemulator to connect to an analog site over the cellular network? ........................75
Can the Modemulator be connected to the console port of a Cisco router? ..................................... 75
Glossary of Terms ..................................................................................................................... 77

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Support....................................................................................................................................78
Appendicies .............................................................................................................................. 80
Appendix A: ASCII Chart......................................................................................................... 80
Appendix B: Excessive Data Usage Warning .............................................................................. 82
Appendix C: DTE Interface Requirements .................................................................................. 84
Appendix D: Result Codes ....................................................................................................... 85
Appendix E: ATI6 Disconnect Reasons ...................................................................................... 86
Appendix F: Flow Control ........................................................................................................ 87
Appendix G: Dial Security ....................................................................................................... 88
Overview ........................................................................................................................... 88
Setting Up Caller ID Screening.............................................................................................. 89
Setting Up Password Prompting ............................................................................................ 91
Setting Up Dialback Security ................................................................................................93
Appendix H: Remotely Accessing and Configuring the Modemulator.............................................. 96
Overview ........................................................................................................................... 96
Setting Up for Remote Access ...............................................................................................97
Starting A Remote Access Session......................................................................................... 97
Ending A Remote Access Session .......................................................................................... 98
Appendix I: Flashing New Firmware into Modemulator Card.........................................................99
Appendix J: DB9 Pinouts ....................................................................................................... 102
Terminal Port.................................................................................................................... 102
Modem Port...................................................................................................................... 102
Appendix K: Peer-To-Peer Cellular Data Service ....................................................................... 103
Appendix L: Leased Line Operation......................................................................................... 104
Appendix M: Break Sequence Operation.................................................................................. 105
Legal Notice............................................................................................................................ 106

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Warranty ............................................................................................................................ 107
Regulatory Information ............................................................................................................ 111
FCC Compliance ................................................................................................................... 111
UL Listing/CUL Listing ........................................................................................................... 111
Industry Canada (IC)............................................................................................................ 111
CE Compliance..................................................................................................................... 112
WEEE Compliance ................................................................................................................ 112
Copyright Information.............................................................................................................. 113

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About This Guide
This Modemulator User Guide contains operating instructions for the USRobotics Courier Modemulator. It
describes the characteristics of the Modemulator when operating in Modemulator mode. For guidance on
the Modemulator operating in Gateway mode, refer to the USR3520/USR803520 Gateway User Guide.
Chapter 1 summarizes some of the key features of the Modemulator, and presents its external interfaces.
Chapter 2 explains how to verify that the Modemulator is operational and how to test the cellular
connectivity before installing the Modemulator into specific deployments.
Chapter 3 shows the intended applications of the Modemulator, and describes its operation in those
applications.
Chapter 4 is a detailed listing of the Modemulator command set with examples of command usage.
Chapter 5 lists Modemulator technical specifications.
Symbols Used In This User Guide
This symbol invites the User to read more technical details.
This symbol identifies helpful User information.
This symbol warns the User to stop, read, and understand critical information.
This symbol denotes supplemental information.

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Important Safety Instructions
General Recommendations For Use
do not open your product when powered.
do not expose to liquid, moisture or humidity.
do not drop, throw or try to bend your product.
do not paint your product.
do not touch the antenna unnecessarily.
Ambient Temperatures
Do not operate your product at ambient temperatures beyond the range of -30 and +70 degrees Celsius
(exception: PoE functionality is limited to 45°C when using more than 30W). When using an AC adapter
make sure that the ambient temperature doesn’t exceed the specified temperature limits of the AC
adapter.
In restricted areas, such as dedicated equipment rooms or electrical closets, where the temperature can
exceed 65°C, the temperature of the surface might reach high values and therefore under these
conditions the products need to be protected against accidental contact. We recommend that operators
who plan to use this product at these high temperatures stick a warning sticker, in accordance with IEC
60417-5041 (DB:2002-10), on a visible part of the device, or attach a sticker with the following text:
WARNING
HOT SURFACE
DO NOT TOUCH
Explosive Atmosphere
Turn off your device in any area with a potentially explosive atmosphere. It is rare, but your device could
generate sparks, which could cause an explosion or fire. Areas with a potentially explosive atmosphere are
Please read the following guidelines carefully. Not following these guidelines can cause
harm to the gateway, yourself or other persons.
RF EXPOSURE WARNING
A minimum distance of 20cm must be maintained between the user's body
and the device antennas.

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not always clearly marked. They include fueling areas (petrol filling stations), below deck on boats, fuel or
chemical transfer or storage facilities and areas where the air contains chemicals or particles, such as
grain, dust, or metal powders. Do not transport or store your product in the compartment of a vehicle
which contains flammable gas, liquid or explosives.
Blasting Areas –Construction Sites
Turn off your product when in a blasting area in order to avoid interfering with two-way radios used in
blasting operations.
Do Not Use On Aircraft
Using wireless devices on aircraft can cause interference. Do not use it when the plane is on the ground
without permission from the aircraft crew.
Driving
Do not operate your device while driving. Park the vehicle first.
Medical Equipment
Do not use near medical equipment, especially life support equipment that might be susceptible to radio
interference.
ESD Notice
Electrostatic Discharge (ESD) is caused by a buildup of static electricity and can happen when making
contact with a product. To limit the likelihood of Electrostatic Discharge, it is recommended to:
avoid conditions that result in high static electricity (carpet, cool and dry air,…);
avoid touching any connectors when handling the unit; only touch the casing if possible;
ground yourself prior to handling by touching a large metal object.
In case the product encounters loss of performance after an Electrostatic Discharge, please reset the
device in order to restore it to normal functionality.
Class A Device
This is a Class A product. In a domestic environment this product may cause radio interference in which
case the User may be required to take adequate measures. The operation of the gateway is restricted for
use in a commercial, industrial or business environment.

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Chapter 1: Features
Introduction
The USRobotics Courier Modemulator allows a legacy M2M system to be conveniently converted to cellular
without upgrading or replacing application software. The Modemulator accepts and responds to analog
modem commands and sends result codes that mimic a PSTN connection, which allows drop-in
compatibility with legacy application software.
Overview of Main Features
The following features and capabilities assure an easy transition from dial-up to cellular M2M.
Cellular Gateway Engine
The Modemulator is embedded into a full-featured cellular gateway, and connects to cellular networks
using the gateway resources.
Operating Modes
The Modemulator operates in two distinct modes, which are selected by a MODE switch on the front of the
device.
Modemulator mode
Gateway mode
Modemulator Mode
In Modemulator mode, the Modemulator’s command line user interface emulates the behavior of a serial
dial-up modem connecting over the PSTN.
Modem AT command set
Originate or answer calls
PSTN response codes
Translate up to 7200 phone numbers into IP addresses
Cellular Gateway Mode
When in cellular gateway mode, the Modemulator configures the base unit to operate as a full-featured
cellular gateway. Some of the key gateway features are:
Interoperability with most cellular networks
GPS receiver
One 10/100 Mbps RJ45 Ethernet port
One DB9 RS-232 DCE serial port
IPsec VPN
Firewall
Graphical User Interface

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Automatic Switchover to Dial-up
To facilitate the gradual conversion of legacy systems to cellular or a permanently mixed system, the
Modemulator can initiate and answer connections over the PSTN to sites with a dial-up modem by
automatically diverting commands to a dial-up modem attached to its Modem serial port. This provides the
User a single interface and protocol for connecting with both cellular and dial-up sites.
Dial Security
The Modemulator provides three forms of dial security for your connections, similar to those of a dial-up
modem.
Programmable Login & Security Banners
The Modemulator can display a programmable login banner if Password Prompting is enabled, and display
a programmable warning banner to alert unauthorized Users, similar to those of a dial-up modem.
HELP Screens
The Modemulator displays screens that summarize the AT command set, Dial command options, and S-
register functions, similar to those of a dial-up modem.
Remote Access
The Modemulator settings can be configured remotely as well as locally, similarly to a dial-up modem.
Firmware Upgrades
The Modemulator firmware is upgradable locally or remotely, allowing easy access to the latest
Modemulator features and functions.

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Physical Features
1. WWAN Diversity Antenna Connector - SMA-female antenna port for connection to a diversity
antenna or a GPS antenna. See the USR3520/USR803520 Gateway User Guide for details.
2. Gateway LEDs –The seven Gateway LEDs indicate the operating status of the Gateway base unit.
See the USR3520/USR803520 Gateway User Guide for details.
3. Ethernet Port –10/100 Mbps RJ-45. See the USR3520/USR803520 Gateway User Guide for details.
4. WWAN Main Antenna Connector - SMA-female antenna port for connection to a cellular antenna.
See the USR3520/USR803520 Gateway User Guide for details.
5. Terminal Serial Port - The terminal serial port provides an RS-232 asynchronous serial DCE
connection via a DB9-F connector. See Appendix J for pinout details. Use an appropriate serial cable to
connect this port to the DTE serial port of a terminal that will send modem AT commands to the
Modemulator. In gateway mode, this port is configured and activated by the Plugin tab of the gateway’s
graphical user interface.
6. Mode Switch –This switch selects the operating mode. See Table 1 below for details.
1
2
4
5
6
7
8
2
3

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7. Modemulator LEDs - These LEDs indicate the Modemulator operating mode and connection status.
See Table 1 for details.
CONNECT
LED
MODE
LED
Switch
Position
Modemulator
mode
Connected
Green
Green
←
Connection pending
(Originate or Answer)
Blinking
Green
←
Ready
Off
Green
←
Busy
Red
Green
←
Gateway mode
Off
Red
→
Power OFF
Off
Off
N/A
Table 1
8. Modem Serial Port - The modem serial port provides an RS-232 asynchronous serial DTE connection
via a DB9-M connector. See Appendix J for pinout details. Use an appropriate serial cable to connect this
port to the DCE serial port of a dial-up modem to enable the Modemulator to manage PSTN connections to
or from remote dial-up modems. In gateway mode, this port is inactive.

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9. External Power Supply Input –This input receives operating power from the external low voltage
power supply that is included with the base unit. Connect the included power supply to this connector. See
the USR3520/USR803520 Gateway User Guide for details.
10. Reset Button - Press and hold for less than five seconds to reset the unit to the last working settings.
Press and hold for five seconds or more to reset the unit to factory settings. See the USR3520/USR803520
Gateway User Guide for details.
Mounting Instructions
The gateway can be mounted on a wall or DIN rail. See the USR3520/USR803520 Gateway User Guide for
details.
9
10

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Chapter 2: Getting Started
This chapter describes:
Verifying Modemulator Operation
Testing Modemulator Connectivity
For detailed configuration and advanced operating features see the Modemulator Command Reference
section in this guide, and see the USR3520/USR803520 Gateway User Guide.
Verifying Modemulator Operation
Because Modemulators make a peer-to-peer connection to another Modemulator, it is required to
perform this set-up procedure on two Modemulators.
For the USR3520/USR803520, please proceed directly to step 1.
For the USR3516-EMU upgrade kit, first follow the instructions in the USR3516-EMU Installation Guide to
upgrade a USR3510/USR803510 Gateway to a USR3520/USR803520.
1. Check system requirements:
Computer with an DB9 RS-232 serial port
Terminal emulation application that communicates with a COM port
If the computer does not have a serial port, use a USB-to-serial cable that is compatible with the
computer’s operating system.
2. Connect a computer to the Modemulator.
Use a DB9-to-DB9 serial cable to connect the computer’s serial port to the Modemulator Terminal
port.
Serial cables are widely available from electronics distributors and retailers.
3. Connect the included power supply unit (PSU) to the base unit.
Use the included PSU to power the base unit. Connect the PSU output jack to the power supply
input, and then plug the PSU into a mains power outlet.
The Modemulator will take about two minutes to become operational.

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MODE
4. Put the Modemulator into Modemulator mode by moving the MODE switch to the left if not already
there.
The MODE LED will be green when the Modemulator is switched into Modemulator mode.
5. Open a Terminal Emulation Application.
Open a terminal emulation window on the computer and select the COM port corresponding to the
computer’s serial port (usually COM1). Set the port parameters for 9600bps, 8 data bits, no parity,
1 stop bit.
Refer to the terminal emulation application documentation for details on setting parameters. It is
recommended to set the application’s font for Courier, Courier New, or another fixed character
width font to properly display the Modemulator screens.
6. Confirm communication with the Modemulator.
In the terminal emulation window, type AT<Enter>. The Modemulator should respond OK.

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Type ATI7<Enter>. The Modemulator should display the I7 information screen, as shown in
Figure 1. Actual parameter values may vary from Figure 1.
Figure 1
The Modemulator is now operational and ready to connect to the cellular network.
If the Modemulator does not respond to AT commands, remove power from the base unit and check the
Troubleshooting section.
ATI7
USRobotics Courier EMU Configuration Profile...
Product type Modemulator
Product ID USR3516-EMU
Code Date 09/08/15
Code Rev 1.0.02
Modemulator S/N 1MENB2AP0001
Cellular S/N MB19D7K4WK
IMEI/MEID 356144040545432
IMSI 310410657302303
F/W Version m2m-1.46.0.2
S/W Version "USRobotics_V1.0.38"
Date/Time 2015-09-09/10:26:03
Internet State connected
WWAN Reg State registered
Operator AT&T
Carrier IP Addr 10.16.212.55
Signal Strength -73
ECIO -11
APN a105.2way.net
OK

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Testing Modemulator Connectivity
Because Modemulators make a peer-to-peer connection to another Modemulator, it is required to
perform this set-up procedure on two Modemulators.
System requirements
A computer with
otwo DB9 RS-232 serial ports
oAn Ethernet port
Terminal emulation application that communicates with COM ports
Web browser application
Or
Two computers, each with
oone DB9 RS-232 serial port
oAn Ethernet port
Terminal emulation application that communicates with COM ports
Web browser application
If the computer does not have a serial port, use a USB-to-serial cable that is compatible with the
computer’s operating system.
Set Up Cellular Connectivity
1. Attach both of the included antennas to the antenna connectors on the front of the Modemulator.
2. Make sure that a cellular service plan is associated with the device (for CDMA networks) or with a
SIM card (for GSM networks).
Modemulator functionality requires a cellular service plan that has device-to-device IP routing.
This type is service is generally not available directly from Mobile Network Operators, so contact a
Mobile Virtual Network Operator (MVNO) to obtain a suitable service plan. See Appendix K for
details. Contact a USRobotics Sales representative for advice on finding a suitable service plan.
Preparing for GSM Networks
1. Remove power from the Modemulator.
2. Install the SIM (for GSM networks):
a. Remove the four Torx T6 screws from the top cover plate on the back of the unit and
remove the plate.

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The MVNO will provide a document listing the peer-to-peer static IP address assigned to this SIM.
Make note of this IP address for later use.
b. Insert the SIM into the SIM slot as shown in Figure 2.
Figure 2
c. Replace the top cover plate and its four TorxT6 screws.
Preparing for CDMA Networks
Devices connecting to a CDMA network do not require a SIM. After the MVNO has provisioned the data
service, the Modemulator will automatically activate itself onto the CDMA network.
The MVNO will provide a document listing the peer-to-peer static IP address assigned to this
device. Make note of this IP address for later use.
Connecting to the Cellular Network
1. Power up the Modemulator by plugging the provided power supply into the connector on the back
of the device.
The Modemulator will take about two minutes to become operational.
The Modemulator card uses the gateway resources for cellular connectivity. So the gateway must
be setup for cellular connectivity before using Modemulator functionality.
2. Use an Ethernet cable to connect the gateway’s Ethernet port to and a computer Ethernet port.
3. Open a web browser on the computer and enter the address 192.168.1.1 into the address bar.
Enter the default username (admin) and password (admin). After a successful login, the Home
screen will appear.

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4. Click on the “Interfaces” tab on the top menu bar and select 3G connection.
5. In the “General” section, select the radio firmware for the wireless service provider that you are
using. Click “Save changes”.
6. Verify/Update the gateway APN to match the network APN provided by the MVNO.
For GSM wireless service:
The network settings will populate automatically for many SIM cards. Check the settings of
the APN, Username, Password, and International Roaming. Update if necessary.
Click “Save changes”.
For CDMA service:
For both Verizon Wireless and Sprint services the activation will occur automatically.
Click on the “Home” tab on the top menu bar.
Connection to the network will be setup automatically.
7. Disconnect the Ethernet cable.
Configure Modemulator Dialing Directory
The Modemulator makes a peer-to-peer connection to another Modemulator, which emulates a
dial-up modem connecting to another dial-up modem. In both cases, the calling device has to
know the “number” of the answering device.
For an M2M system based on dial-up modems and PSTN networks, the telephone service provider
assigns a phone number to the destination, and the User (or software application) commands the
calling modem to dial the phone number of the destination modem.
For an M2M system based on Modemulators and cellular networks, the MVNO that provides the
cellular data service will assign a static IP address to each device (CDMA) or SIM (GSM) on the
account. That IP address is the “number” that the calling device must know.
In order for the Modemulator to be a drop-in replacement for dial-up modems, it has to accept a
command to dial a PSTN phone number, but translate that number into the IP address of the
destination Modemulator. That translation is done by the Modemulator dialing directory.
WARNING!
LAN to WAN routing is enabled by default. Once connected, any
Internet activity on your system will consume Cellular Data.
For configuration and more information go to Appendix B