NAL A3LA-RM User manual

Copyright © 2021 by NAL Research Corporation
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Manassas, Virginia 20109 USA
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Email: [email protected]
A3LA-RM User Guide
Version B
April 4, 2022
451-93156-002B

AL3A-RM User Guide Version B
Document Number: 451-93156-002B 2 of 172
LEGAL DISCLAIMER AND CONDITION OF USE
This document contains information for the A3LA-RM modem and accompanying accessories
(“Product”), which is provided “as is.” Reasonable effort has been made to make the information
in this document reliable and consistent with specifications, test measurements and other
information. However, NAL Research Corporation and its affiliated companies, directors, officers,
employees, agents, trustees or consultants (“NAL Research”) assume no responsibility for any
typographical, technical, content or other inaccuracies in this document. NAL Research reserves
the right in its sole discretion and without notice to you to change Product specifications and
materials and/or revise this document or withdraw it at any time. User assumes the full risk of
using the Product specifications and any other information provided.
NAL Research makes no representations, guarantees, conditions or warranties, either express
or implied, including without limitation, any implied representations, guarantees, conditions or
warranties of merchantability and fitness for a particular purpose, non-infringement, satisfactory
quality, non-interference, accuracy of informational content, or arising from a course of dealing,
law, usage, or trade practice, use, or related to the performance or nonperformance of any
products, accessories, facilities or services or information except as expressly stated in this guide
and/or the Product and/or satellite service documentation. Any other standards of performance,
guarantees, conditions and warranties are hereby expressly excluded and disclaimed to the
fullest extent permitted by the law. This disclaimer and exclusion shall apply even if the express
limited warranty contained in this guide or such documentation fails of its essential purpose.
In no event shall NAL Research be liable, whether in contract or tort or any other legal theory,
including without limitation strict liability, gross negligence or negligence, for any damages in
excess of the purchase price of the Product, including any direct, indirect, incidental, special or
consequential damages of any kind, or loss of revenue or profits, loss of business, loss of privacy,
loss of use, loss of time or inconvenience, loss of information or data, software or applications or
other financial loss caused by the Product (including hardware, software and/or firmware) and/or
the Iridium satellite, or arising out of or in connection with the ability or inability to use the
Product (including hardware, software and/or firmware) and/or the Iridium satellite to the fullest
extent these damages may be disclaimed by law and whether advised of the possibilities of such
damages. NAL Research is not liable for any claim made by a third party or made by you for a
third party.

AL3A-RM User Guide Version B
Document Number: 451-93156-002B 3 of 172
REVISION HISTORY
Revision
Date
Description
1.3
8/2/16
Initial version
A
5/20/20
Added revision history
Updated address
Updated document number
Added AT^VOLB command
A.1
06/09/2021
Updated to new template; proofread.
B
03/08/2022
Formal release

AL3A-RM User Guide Version B
Document Number: 451-93156-002B 4 of 172
REFERENCE DOCUMENTS
The latest revisions of the NAL documents are available from the NAL Research website at
https://www.nalresearch.com/support/documentation-downloads/.
Reference
Title
Revision/Date
[1]
A3LA-RM Product Information
05/03/2019
[2]
Getting Started With Model A3LA-RM (TN2012-21-
V1.1)
04/08/2013
[3]
SatTerm Software Manual (TN451-94000-001A)
Version A, 20122
[4]
Additional Information on DirectIP SBD (TN2007-637-
V1.0)
02/01/2007
[5]
Additional Information on SBD (AN2012-04-V4.0)
02/01/2012

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TABLE OF CONTENTS
1Introduction............................................................................................................... 17
2Multi-interface Connector.......................................................................................... 19
2.1 RS232 Data Interface (Standard 9-Wire Configuration)..................................................... 20
2.2 RS232 Data Interface (3-Wire Configuration)..................................................................... 20
2.3 DC Power Input................................................................................................................... 21
2.4 Power On/Off Control......................................................................................................... 22
2.5 Audio Interface ................................................................................................................... 23
2.6 Digital Peripheral Link (DPL)................................................................................................ 24
3Antenna Connector .................................................................................................... 25
4SIM Card Interface ..................................................................................................... 27
5LED Display ................................................................................................................ 28
6Configuration Settings................................................................................................ 29
7Modes of Operation................................................................................................... 30
8AES-256 Bit Encryption............................................................................................... 31
9Self-monitoring to Prevent Modem Lockup ................................................................ 32
10 Mounting Recommendations ..................................................................................... 33
11 Technical Support ...................................................................................................... 34
12 Appendix A: AT Interface............................................................................................ 35
12.1 Command Types ................................................................................................................. 35
12.2 Basic Commands................................................................................................................. 35
12.3 Extended Commands.......................................................................................................... 35
12.4 Command and Response Characters.................................................................................. 37
12.5 Command Entry .................................................................................................................. 37
12.6 Command Responses.......................................................................................................... 38
12.7 Hardware Failure Reporting................................................................................................ 39
Appendix B: AT Command Set Description ........................................................................ 40
(Iridium Radio Link Protocol) ........................................................................................................ 40
B.1 AT –Attention Code............................................................................................................ 40
B.2 A/ –Repeat Last Command ................................................................................................ 40
B.3 +++ –Escape Sequence....................................................................................................... 40
B.4 En –Echo............................................................................................................................. 40

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B.5 On –Online ......................................................................................................................... 40
B.6 Qn –Quiet Mode ................................................................................................................ 40
B.7 Vn –Verbose Mode ............................................................................................................ 41
B.8 Wn –Error Correction Message Control ............................................................................ 41
B.9 Zn –Soft Reset .................................................................................................................... 41
B.10 &Cn –DCD Option ................................................................................................................ 41
B.11 &Dn –DTR Option............................................................................................................... 41
B.12 &Fn –Restore Factory Settings........................................................................................... 42
B.13 &Kn –Flow Control............................................................................................................. 42
B.14 &Mn –Asynchronous/Synchronous Mode......................................................................... 42
B.15 &Qn –Sync/Async Mode .................................................................................................... 42
B.16 &Sn –DSR Override ............................................................................................................ 43
B.17 &V –View Active and Stored Configuration....................................................................... 43
B.18 &Wn –Store Active Configuration...................................................................................... 43
B.19 &Yn –Designate Default Reset Profile ............................................................................... 43
B.20 \Kn –Control Break............................................................................................................. 43
B.21 %R –Display Registers ........................................................................................................ 44
B.22 *Pn –Power ........................................................................................................................ 44
B.23 +CBST –Select Bearer Service Type.................................................................................... 44
B.24 +CGMI –Manufacturer Identification ................................................................................ 45
B.25 +CGMM –Model Identification .......................................................................................... 45
B.26 +CGMR –Revision............................................................................................................... 45
B.27 +CGSN –Serial Number ...................................................................................................... 45
B.28 +CMEE –Report Mobile Equipment Error.......................................................................... 45
B.29 +CPAS –Modem Activity Status ......................................................................................... 47
B.30 +CR –Service Reporting Control......................................................................................... 48
B.31 +DS –Set Data Compression Function................................................................................ 48
B.32 +DR –Data Compression Report Level ............................................................................... 49
B.33 +CEER –Extended Error Report.......................................................................................... 50
B.34 +CHUP –Hangup call........................................................................................................... 50
B.35 +CMGD –Delete SMS Message .......................................................................................... 51
B.36 +CMGF –SMS Message Format.......................................................................................... 53

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B.37 +CMGL –List SMS Messages............................................................................................... 54
B.38 +CMGR –Read SMS Message............................................................................................. 55
B.39 +CMGS –Send SMS Message.............................................................................................. 56
B.40 +CMGW –Write SMS Message To Memory....................................................................... 56
B.41 +CMOD –Call Mode............................................................................................................ 57
B.42 +CNMI –New SMS Message Indications to DTE................................................................. 57
B.43 +COPS –Operator Select .................................................................................................... 59
B.44 +CPBF –Find Phonebook Entries........................................................................................ 60
B.45 +CPBR –Read Phonebook Entries ...................................................................................... 61
B.46 +CPBS –Select Phonebook Storage.................................................................................... 61
B.47 +CPBW –Write Phonebook Entry....................................................................................... 62
B.48 +CPIN –Enter PIN................................................................................................................ 63
B.49 +CPMS –Select Preferred SMS Message Storage .............................................................. 64
B.50 +CREG –Network Registration ........................................................................................... 65
B.51 +CSCA –SMS Service Center Address................................................................................. 66
B.52 +CSCB –Select Cell Broadcast Message Types ................................................................... 66
B.53 +CSCS –Select TE Character Set ......................................................................................... 67
B.54 +CSMS –Select SMS Message Service................................................................................ 67
B.55 +CSTA –Select Type of Address.......................................................................................... 68
B.56 +GMI –Manufacturer Identification................................................................................... 68
B.57 +GMM –Model Identification ............................................................................................ 68
B.58 +GMR –Revision................................................................................................................. 69
B.59 +GSN –Serial Number......................................................................................................... 69
B.60 +GCAP –General Capabilities ............................................................................................. 69
B.60.1A –Answer.......................................................................................................................... 69
B.62 D –Dial................................................................................................................................ 69
B.62.1 D> –Direct Dial From Phonebook ..................................................................................... 70
B.63 Hn –Hangup........................................................................................................................ 70
B.64 S0=n –Auto-Answer ........................................................................................................... 71
B.65 Xn –Extended Result Codes ............................................................................................... 71
B.66 +CLVL –Volume Level Control............................................................................................ 71
B.67 +CMUT –Mute Control....................................................................................................... 72

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B.68 +CRC –Cellular Result Codes .............................................................................................. 73
B.69 +CVHU –Voice Hangup Control.......................................................................................... 73
B.70 +CCLK –Real-Time Clock..................................................................................................... 74
B.71 –MSVTS –DTMF Generation in Voice Call............................................................................ 74
B.72 –MSVTR –DTMF Received in Voice Call ............................................................................. 75
B.73 –MSVLS –Local DTMF Feedback Selection........................................................................... 76
B.74 –MSSTM –Request System Time ......................................................................................... 76
B.75 –MSGEO –Request Geolocation .......................................................................................... 77
B.76 +CCFC –Call Forward Service ............................................................................................... 78
B.77 +CLCC –Request Current Call Status .................................................................................. 80
B.78 +CNUM –Read MSISDN Numbers........................................................................................ 80
B.79 +CSSSC –Supplementary Services Shortcode ...................................................................... 80
B.80 +WIRLP –Iridium Radio Link Protocol .................................................................................. 81
B.81 +WFRNG –Force IRLP Renegotiation ................................................................................... 83
B.82 +WTM –IRLP Test Mode..................................................................................................... 83
B.83 +WDLDM –IRLP Dynamic Link Delay Measurement............................................................ 84
B.84 +WDAV –Register or Deregister an RS232 DAV Data Peripheral....................................... 84
B.85 +SBDWB –Short Burst Data: Write Binary Data................................................................. 85
B.86 +SBDRB –Short Burst Data: Read Binary Data ................................................................... 86
B.87 +SBDRT –Short Burst Data: Read Text Message................................................................ 86
B.88 +SBDD –Short Burst Data: Clear SBD Message Buffer(s)................................................... 87
B.89 +SBDC –Short Burst Data: Clear SBD MOMSN................................................................... 88
B.90 +SBDS –Short Burst Data: Status........................................................................................ 88
B.91 +SBDTC –Short Burst Data: Transfer MO Buffer to MT Buffer .......................................... 89
B.92 +CAR –Audio Output Control............................................................................................. 89
B.93 In –Identification................................................................................................................ 89
B.94 +CIER –Indicator Event Reporting...................................................................................... 90
B.95 +CRIS –Ring Indication Status ............................................................................................ 92
B.96 +CSQ[F] –Signal Quality...................................................................................................... 92
B.97 +CULK –Unlock................................................................................................................... 93
B.98 +CVMI –Voicemail Indication............................................................................................. 94
B.99 +CICCID –Read ICC ID from SIM ......................................................................................... 95

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B.100 +CLIP –Calling Line Identification Presentation................................................................. 95
B.101 +CLIR –Calling Line Identification Restriction .................................................................... 96
B.102 +IPR –Fixed DTE Rate ......................................................................................................... 97
B.103 +SBDWT –Short Burst Data: Write a Text Message........................................................... 97
B.104 +SBDDET –Short Burst Data: Detach ................................................................................. 98
B.105 +SBDI –Short Burst Data: Initiate an SBD Session............................................................ 100
B.106 +SBDIX[A] –Short Burst Data: Initiate an SBD Session Extended .................................... 101
B.107 +SBDDSC –Short Burst Data: Delivery Short Code........................................................... 104
B.108 +SBDMTA –Short Burst Data: Mobile-Terminated Alert ................................................. 105
B.109 +SBDREG –Short Burst Data: Network Registration........................................................ 105
B.110 +SBDAREG –Short Burst Data: Automatic Registration................................................... 108
B.111 +SBDSX –Short Burst Data: Status Extended................................................................... 110
B.112 +CCWA –Call Waiting service........................................................................................... 111
B.113 +CLCK –Facility Lock ......................................................................................................... 113
B.114 +CPWD –Change Password.............................................................................................. 116
B.115 +CSDT –Sidetone.............................................................................................................. 117
B.116 +CDSI –Report SMS status ............................................................................................... 117
B.117 +GPSSTA –Configure GPS Status...................................................................................... 119
B.118 +PA –GPS: List of NMEA Message Formats...................................................................... 119
B.119 +PLOC –GPS: Display Position to 5th Decimal Place......................................................... 120
B.120 ^AA –Auto Answer Display............................................................................................... 120
B.121 ^AD –Auto Dial................................................................................................................. 120
B.122 ^ADR –Auto Dial Retry ..................................................................................................... 121
B.123 ^CCOP –Change Crypto Officer Password (Encryption) .................................................. 121
B.124 ^CMGEC –Clear SMS Encrypted Storage ......................................................................... 121
B.125 ^FFW –Flash Firmware..................................................................................................... 122
B.126 ^KD –Key for Decryption (Encryption)............................................................................. 122
B.127 ^KE –Key for Encryption (Encryption).............................................................................. 122
B.128 ^KZ –Key Zeroization (Encryption)................................................................................... 123
B.129 ^MODRSTn –Modem Reset Information Message Displayed......................................... 123
B.130 ^MPTDC- Modem Power Toggle Data Connection .......................................................... 123
B.131 ^MPTFP- Modem Power Toggle Forced Power-cycle ...................................................... 124

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B.132 ^MPTFR- Modem Power Toggle Forced Registration ...................................................... 125
B.133 ^MPTNC- Modem Power Toggle Not in Data Connection ............................................... 125
B.134 ^MSB –Motion Sensor Begin ........................................................................................... 126
B.135 ^PKTS –Use Packets ......................................................................................................... 126
B.136 ^PKTST –Packet Send Timer............................................................................................. 127
B.137 ^PKTRT –Packet Resend Timer ........................................................................................ 127
B.138 ^PKTTH –Packet Send Threshold ..................................................................................... 128
B.139 ^RESETMODEMTG –Reset Modem Toggle...................................................................... 128
B.140 ^RESETMODEMVF –Reset Modem Verify ....................................................................... 128
B.141 ^RLE –Use Run Length Encoding...................................................................................... 129
B.142 ^SE –Configure Streaming Encryption............................................................................. 129
B.143 ^SMSD –SMS Delete ........................................................................................................ 130
B.144 ^SMSE –SMS Erase........................................................................................................... 130
B.145 ^SMSR –SMS Read ........................................................................................................... 130
B.146 ^SSI –Send Start-Up Information..................................................................................... 131
B.147 ^STR –Self Test Run (Encryption)..................................................................................... 131
B.148 ^UE –Use Encryption ....................................................................................................... 131
B.149 ^VOLB –Volume Boost..................................................................................................... 132
Appendix C: S-Register Definitions..................................................................................... 133
C.1 S-Register Commands....................................................................................................... 133
C.1.1 Sr –Direct S-Register Reference....................................................................................... 133
C.1.2 Sr? –Direct S-Register Read............................................................................................. 133
C.1.3 Sr=n –Direct S-Register Write.......................................................................................... 133
C.1.4 Referenced S-Register Read............................................................................................. 133
C.1.5 =n –Referenced S-Register Write .................................................................................... 133
C.2 Standard S-Registers......................................................................................................... 134
C.3 Iridium Specific S-Register Extensions.............................................................................. 137
Appendix D: Summary of Result Codes .............................................................................. 141
Appendix E: Informative Examples..................................................................................... 145
E.1 Unit Identification............................................................................................................. 145
E.2 Setting the Default Configuration..................................................................................... 146
E.3 Power-on to Sending an SBD Message............................................................................. 146

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E.4 SBD Automatic Notification Registration.......................................................................... 147
E.5 SBD Automatic Notification Message Reception.............................................................. 148
E.6 SBD Automatic Notification Automatic Registration........................................................ 149
E.7 Originating a Data Call ...................................................................................................... 149
E.8 Answering a Data Call ....................................................................................................... 150
E.9 Disconnecting a Data Call ................................................................................................. 150
E.10 Coordination of +CLCC and +CPAS responses................................................................... 151
Appendix F: Power Consumption....................................................................................... 153
Appendix G: The Iridium Network...................................................................................... 160
G.1 Iridium Network Data Capabilities.................................................................................... 161
G.2 Dial-up Data Service.......................................................................................................... 162
G.3 Direct Internet Connection............................................................................................... 164
G.4 Short Burst Data................................................................................................................ 165
G.5 Short Messaging Service................................................................................................... 165
G.6 RUDICS .............................................................................................................................. 166
G.7 Iridium Geolocation .......................................................................................................... 166
Appendix H: Standards Compliance ................................................................................... 167
Appendix I: MIL-STD-810G Certification ............................................................................. 168
Appendix J: Export Compliance.......................................................................................... 169
Appendix K: Design Specifications...................................................................................... 170
K.1 Mechanical Specifications................................................................................................. 170
K.2 RF Specifications ............................................................................................................... 170
K.3 Electrical Specifications..................................................................................................... 170
K.4 Environmental Specifications ........................................................................................... 171
K.5 Data I/O Specifications...................................................................................................... 171
K.6 Related Hardware ............................................................................................................. 171
Appendix L: Mechanical Drawing....................................................................................... 172

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TABLE OF FIGURES
Figure 1: Iridium Satellite Modem A3LA-RM................................................................................ 17
Figure 2: Power Input Setting for the A3LA-RM ........................................................................... 22
Figure 3: A3LA-RM Connected to a DPL Handset via the HRC-24-8R........................................... 24
Figure 4: Location of the SIM Reader ........................................................................................... 27
Figure 5: Iridium Satellite Modem A3LA-RM................................................................................ 28
Figure 6: Average Current Drawn During Standby ..................................................................... 154
Figure 7: Average Power Consumption During Standby ............................................................ 154
Figure 8: Average Current Drawn During Standby with DPL Handset........................................ 155
Figure 9: Average Power Consumption During Standby with DPL Handset............................... 155
Figure 10: Average Current Drawn During a Data Switch Call.................................................... 156
Figure 11: Average Power Consumption During a Data Switch Call........................................... 156
Figure 12: Average Current Drawn During an SBD Transmission............................................... 157
Figure 13: Average Power Consumption During an SBD Transmission...................................... 157
Figure 14: Average Current Drawn During an SMS Transmission .............................................. 158
Figure 15: Average Power Consumption During an SMS Transmission ..................................... 158
Figure 16: Average Current Drawn During a Voice Call Using DPL Handset .............................. 159
Figure 17: Average Power Consumption During a Voice Call Using DPL Handset ..................... 159
Figure 18: Iridium Network Major Components ........................................................................ 160
Figure 19: Iridium Network Data Capabilities............................................................................. 162
Figure 20: PSTN Dial-up Connectivity ......................................................................................... 163
Figure 21: Iridium Dial-up Data Service ...................................................................................... 164
Figure 22: Mil-STD-810G Certification........................................................................................ 168
Figure 1: A3LA-RM Mechanical Drawing .................................................................................... 172

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TABLE OF TABLES
Table 1: Pin Assignment for the Multi-interface Connector....................................................... 19
Table 2: General RF Parameters .................................................................................................. 25
Table 3: Custom Antenna Specifications..................................................................................... 25
Table 4: Numeric and Verbose Mode Formats ........................................................................... 39
Table 7: Standard S-Registers .................................................................................................... 134
Table 8: Iridium Specific S-Register Extensions......................................................................... 137
Table 9: V.25ter/Hayes Result Codes ........................................................................................ 141
Table 10: GSM 7.07 Result Codes .............................................................................................. 143
Table 11: GSM 7.05 Result Codes .............................................................................................. 143
Table 12: Iridium Specific Result Codes..................................................................................... 144
Table 13: Unit Identification ...................................................................................................... 145
Table 14: Default Configuration ................................................................................................ 146
Table 15: Sending an SBD Message ........................................................................................... 146
Table 16: SBD Automatic Notification Registration.................................................................. 147
Table 17: SBD Automatic Notification Message Reception...................................................... 148
Table 18: SBD Automatic Notification Automatic Registration................................................ 149
Table 19: Originating a Data Call ............................................................................................... 149
Table 20: Answering a Data Call ................................................................................................ 150
Table 21: Disconnecting a Data Call........................................................................................... 150
Table 22: Coordination of +CLCC and +CPAS Responses .......................................................... 151

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ACRONYM LIST
3GPP...........................3rd Generation Partnership Project
AES .............................Advanced Encryption Standard
ASCII ...........................American Standard Code for Information Interchange
AT ...............................Two-letter sequence starting a string of modem commands. The AT is
intended to get the modem’s attention prior to executing a command.
BIS ..............................Bureau of Industry and Security
CTS..............................Clear to send
DAV ............................Data After Voice
DC...............................Direct current
DCD ............................Data carrier detect
DCE.............................Data circuit-terminating equipment
DoD ............................Department of Defense
DPL .............................Digital Peripheral Link
DSN.............................Defense Switch Network
D-sub..........................D-subminiature
DSR.............................Data set ready
DTE .............................Data terminal equipment
DTMF..........................Dual-tone multi-frequency
DTR.............................Data terminal ready
EAR.............................Export Administration Regulations
EMI .............................Electromagnetic interference
EMSS ..........................Enhanced Mobile Satellite Services
ETSI.............................European Telecommunications Standards Institute
FCC .............................Federal Communications Commission
FDMA .........................Frequency-division multiple access
GMT............................Greenwich Mean Time
GND............................Ground
GPRS...........................General Packet Radio Service
GPS.............................Global Positioning System

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GSM............................Global System for Mobile Communications
IMEI ............................International Mobile Equipment Identification
I/O ..............................Input/output
IP ................................Internet Protocol
IP67 ............................Ingress Protection Code 67
ISP...............................Internet Service Provider
ISU ..............................Iridium subscriber unit (modems, phones, trackers)
LAN.............................Local area network
LBT..............................L-band transceiver
LCD .............................Liquid-crystal display
LED .............................Light-emitting diode
LEO .............................low-earth orbit
NIPRNet......................Non-classified Internet Protocol Router Network
NMEA .........................National Marine Electronics Association
NOC ............................Network Operation Center
OFAC...........................Office of Foreign Asset Controls
PCM............................Pulse-code modulation
PIN..............................Personal identification number
PPP .............................Point-to-point protocol
PSTN...........................Public switched telephone network
RF................................Radio frequency
RH...............................Relative humidity
RHCP...........................Right-handed circular polarization
RI ................................Ring indicator
RTS..............................Request to send
RUDICS .......................Router-based unrestricted digital internetworking connectivity solution
SBD.............................Short-burst data
SIM .............................Subscriber identification module
SMS ............................Short message service
TBR .............................Time Between Reports

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TCP .............................Transmission Control Protocol
TDD.............................Time-division duplex
TDMA .........................Time-division multiple access
TNC.............................Threaded Neill–Concelman
TON ............................Type of number
UART...........................Universal asynchronous receiver-transmitter
VDC.............................Volts (Direct Current)
VSWR..........................Voltage standing wave ratio

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1INTRODUCTION
This user guide provides you with information on the operational features, and electrical and
mechanical interfaces of the A3LA-RM. The A3LA-RM is a satellite modem comprising a 9523 L-
band transceiver (LBT) with an extended input voltage range. The A3LA-RM has an internal
microcontroller programmed to monitor the modem’s connectivity status to prevent hardware
lockup. It is designed to transmit either AES 256-bit encrypted or unencrypted data via the
Iridium satellite network. Similar to a standard landline modem, the A3LA-RM can be controlled
by any data terminal equipment (DTE) capable of sending standard AT commands via an RS232
serial port. A DTE can be a desktop computer, a laptop computer, a smartphone, or even a
microcontroller. The A3LA-RM is functionally compatible with models 9522B, A3LA-R, and
A3LA-RS. It is approximately 60% smaller in volume and 50% lighter than the 9522B. Model
A3LA-RM-MIL is an A3LA-RM that has been certified to MIL-STD-810G standards and IP67
rating.
Services supported include:
Dial-up data switch
Direct Internet connection (or NIPRNet connection)
Direct Internet connection using Apollo Emulator (only for DoD EMSS gateway)
Short message service (SMS)
Short burst data (SBD)
Router-based unrestricted digital internetworking connectivity solution (RUDICS)
Voice when combined with the Digital Peripheral Link (DPL) audio handset
Figure 1: Iridium Satellite Modem A3LA-RM
DB25 Multi-interface Connector
TNC Antenna Connector
SIM Reader under the Lid

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Important: Do not disassemble the A3LA-RM for repair or services. The warranty is voided if the
A3LA-RM is disassembled. Return it to NAL Research for any services.

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2MULTI-INTERFACE CONNECTOR
The multi-interface connector is a male 25-pin miniature D-sub type that includes five
interfaces—RS232, DC input power, ON/OFF control line, analog audio, and DPL. The multi-
interface connector pin assignments are summarized in Table 1, which is ‘pin-to-pin’ the same
as model A3LA-R, A3LA-XM, and A3LA-X.
Table 1: Pin Assignment for the Multi-interface Connector
Pin #
Signal
Description
Interface
1
EXT_ON_OFF
Power on/off control input
DC Power
2
+12VDC
Output voltage to power the DPL handset
DC Power
3
EXT_GND
External GND input
DC Power
4
EXT_B+
External 4.0 V –5.4 V or 5.0 V –32.0 V
DC Power
5
SPKR_AUD
Speaker audio output
Analog Audio
6
DA_TX
PCM digital audio output
Digital Audio
7
RI
RS232 ring indicator
RS232 Data
8
RTS
RS232 request to send
RS232 Data
9
TX
RS232 transmit data (input)
RS232 Data
10
DCD
RS232 data carrier detect
RS232 Data
11
DA_FS
PCM digital audio frame sync output
Digital Audio
12
DA_CLK
PCM digital 2.048 MHz audio clock output
Digital Audio
13
RX
RS232 receive data (output)
RS232 Data
14
SIGNAL GND
Signal ground, 0 V signal reference and return
GND
15
MIC_AUD
Microphone audio input
Analog Audio
16
EXT_B+
External 4.0 V –5.4V or 5.0 V –32.0 V
DC Power
17
EXT_GND
External GND input
DC Power

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Table 1: Pin Assignment for the Multi-interface Connector
Pin #
Signal
Description
Interface
18
DPL_TX
Digital Peripheral Link (DPL) data output
DPL UART
19
DTR
RS232 data terminal ready
RS232 Data
20
DPL_RX
Digital Peripheral Link (DPL) data input
DPL UART
21
DSR
RS232 data set ready
RS232 Data
22
CTS
RS232 clear to send
RS232 Data
23
SIGNAL GND
Signal ground, 0 V signal reference and return
GND
24
DA_RX
PCM digital audio input
Digital Audio
25
SIGNAL GND
Signal ground, 0 V signal reference and return
GND
2.1 RS232 DATA INTERFACE (STANDARD 9-WIRE CONFIGURATION)
The A3LA-RM supports a standard RS232 data interface to a DTE incorporating hardware
handshaking and flow control. The RS232 data interface comprises eight standard RS232 data,
control, and status signals, plus a ground-level signal reference, as shown in Table 1. This
interface allows a connected DTE to utilize the A3LA-RM’s modem functionality through a set of
AT commands. These commands are defined in Appendix A: AT Interface. The factory-set baud
rate is 19,200 bps and can be changed using the +IPR command.
Note that the Ring Indicator is used by the A3LA-RM to indicate that a mobile-terminated SBD
(MT-SBD) message is queued at the gateway. Application developers can monitor this pin and
apply appropriate AT commands to the A3LA-RM to retrieve the MT-SBD message.
2.2 RS232 DATA INTERFACE (3-WIRE CONFIGURATION)
A 3-wire RS232 data interface may also be implemented. Because of risk of overrun and data
loss, especially at high baud rates, the 9-wire interface is the recommended implementation.
Several steps must be taken to allow 3-wire configuration (i.e., only using S_TX, S_RX, and
SIGNAL GND). These steps ensure the A3LA-RM and DTE work together without having
hardware handshaking.