Multi-Tech Systems MT3334SMI manual PC Board Layout Considerations, Recommended Transceiver

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Chapter 1 - Introduction and Description

Safety: All creepages and clearances for the MT3334SMI have been designed to meet requirements of safety standards EN60950 and IEC950. The requirements are based on a working voltage of 250V. When the recommended DAA circuit interface is implemented in a third party design all creepage and clearance requirements must be strictly adhered to. The third party safety design must be evaluated by the appropriate national agency per the required specification.

User accessible areas: Based on where the third party design is to be marketed/sold or used, it may be necessary to provide an insulating cover over all TNV exposed areas. Consult with the recognized safety agency to determine the requirements.

Notice: Even if the recommended design considerations are followed, there are no guarantees that a particular system will comply with all the necessary regulatory requirements. It is imperative that specific designs be completely evaluated by a qualified/recognized agency.

Recommended Transceiver

Manufacturer – Analog Devices

Part # - ADM207EAR

PC Board Layout Considerations

This section discusses the FCC Part 68 and Industry Canada CS-03 Telecom compliance of the Multi-Tech Systems, Inc. Model MT5634SM/SMI socketed modem module.

This module was tested by the NVLAP accredited KTL Dallas Inc. laboratory and conforms to the above said standards. The modem module was tested in the MultiTech MTASR3-200, a 3-modem asynchronous router that uses three socket modems for dial-up telephone access. The developer’s guide (included on diskette) with the MT5634SM/SMI modem includes design specifications listing recommendations for the RJ-11 phone jack and fuse which are needed for FCC Part 68 compliance.

The MTASR3-200 tested has sockets for three modem modules each having traces of varying lengths out to the RJ-11 connectors. Trace lengths ranged from 1.97 to 3.15 inches. The trace widths were all 12 mil. Since three ports with varying trace lengths were tested, we concluded that as long as the customer’s printed circuit board characteristics are reasonably close to these parameters there should not be any issues relating to telecom compliance. In addition to a recommended external fuse, the modem module also has a Sidactor on board.

Multi-Tech believes that, provided the same components are used and parts placement is similar, Telecom compliance will be maintained for the system and no additional testing is required.

Calculating Z for Tip and Ring Traces

Trace Impedance - Side-by-Side Traces

120

 

Zo = Er

1n

p S

w + t

Where: Er = Relative permittivity of the PCB dielectric material. Typically 4 - 4.7

s= Spacing between traces - 12 mils (.012)

w= Trace width - 12 mils (.012)

t= Trace thickness - (.0022)

Zo

 

120

 

=

2.16

1n

Zo

=

54 W

 

.03769

.0142

Note: The trace inductance for the tested design varied from 61nH to 105nH.

MT3334SMI

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Contents Data/Fax Socketed Modem Model MT3334SMI Evaluation KitPatents Revision DescriptionContents Index Introduction and Description ModemModule Developer’s Guide FeaturesIntroduction Product DescriptionIntroduction and Description Technical Specifications1200 bps MT3334SMI Physical Dimensions Physical DimensionsTest/Demo Board Specifications DS1LED1-LED4 MT3334SMI Test/Demo Board Block Diagram Test/Demo Board Block Diagram MT3334SMI Pinout MT3334SMI Pin-outTypical Application Hardware Considerations MT3334SMI Design ConsiderationsPC Board Layout Considerations Calculating Z for Tip and Ring TracesRecommended Transceiver MT3334SMI Placement KeyQty Name Description FCC Part Telecom Labeling RequirementsReregistration Industry Canada CS-03Multiple Listing AT Commands, S-Registers, and Result Codes Answer Repeat Last CommandAT Commands, S-Registers, and Result Codes Result Codes Enable/Disable Monitor Speaker VolumeMonitor Speaker Mode Return Online to Data ModeResult Code Format Modem ResetSr? Read Register Value Tone DialingStore Current Configuration Command &Fn Load Factory SettingsAsynchronous Communications Mode Display Current Settings\Jn Data Buffer Control Command &Zy=x Store Dialing Command\An Select Maximum MNP Block Size \Bn Transmit Break\Vn Protocol Result Code \Nn Error Correction Mode Selection\Tn Inactivity Timer \Qn Flow Control SelectionEnter Setup Password Command %DCn AT Command ControlCommand %En Fallback and Fall Forward Control Command +ES=n Enable Synchronous Buffered ModeRegisters Register Unit Range Default DescriptionS43 Terse Verbose Description Result CodesClass 1 Fax Commands Command Description Class 1 Fax Command SummaryResult Code Meaning Class 1 Fax Commands Fax MOD Modulation Parameter ValuesCommand Function Display Current Class Values Default Data modemModemModule Developer’s Guide Command Function Select Service Class Values Default Data modeFunction +FRS=? Enter Class 1 Fax Commands+FRM=? Enter Flow Control Result CodesSample Sessions Action by Command Respone Local Modem Remote PC AT+FRH=3 No Carrier ModemModule Developer’s Guide Class 2 Fax Commands +FAXERR Class 2 Fax Command ImplementationClass 2 Fax Commands EIA SP-2388 August +FAA+FBOR +FCQ+FCR Current Session Results +FDCCFax Capability Parameters +FDCSCurrent Session Parameters +FDFFCData Compression Format Conversion +FDIS+FET +FDR+FDT +FECM+FLPL +FK+FLID +FLNFC+FSPL +FPTS+FRBC +FREL+FTSI +FHNGMT3334SMI Remote Configuration ModemModule User Guide Basic ProcedureSetup Changing the Setup PasswordChanging the Remote Escape Character Remote ConfigurationMT3334SMI Troubleshooting Local Analog Loopback Test V.54 Loop Test procedureRemote Digital Loopback Test V.54 Loop TroubleshootingLocal digital loopback test Local Digital Loopback Test V.54 LoopUpgrade Procedure Multi-Tech Web Site Upgrade OverviewIdentify the Modem Firmware Identify the Current Firmware VersionDownload the Upgrade File Upgrade ProcedureMulti-Tech BBS Clear Your Stored Paramenters Extract the Upgrade FilesUse FlashPro to Upgrade Modem Firmware Restore Your ParametersAppendixes MT3334SMI Appendixes FCC FAX UpdateInternational Modem Restrictions Canadian Limitations NoticeEMC, Safety and Terminal Directive Compliance European Directives User Guide StatementNew Zealand Telecom Warning Notice Handshake Sequence Appendix B Multi-Tech Flash Programming ProtocolIntroduction Programming the ModemOther supported boot code commands Other programming concernsModemModule Developer’s Guide Program Sequence Intel Hex Format Data RecordXxxx Extended Address Record End of File RecordEeee Index IndexMT3334SM MT3334SMI MT3334SM
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