Fallback Modes When On-Line #F | Black Box MD1640A, MD1641A specs

CHAPTER 5: Command Mode

codings except under an unusual line condition called impulse noise. AT#T0 turns Trellis coding off and AT#T1 turns Trellis coding on (factory default).

Fallback Modes When On-Line #F

If line conditions deteriorate, the Series II Modem automatically drops its transmission speed (“fallback”). The #F command controls the different ways the Modem falls back. During operation, if the error rate becomes too great, the modem performs a retrain. If after the retrain, the error rate is still too high for 33600 bps operation, the modem initiates a retrain at 4800 bps. If after the first retrain the modem returns on line at 33600 bps, the modem then starts a counter and a timer. If three retrains occur within a two minute period, the modem falls back to 4800 bps.

Entering AT#F0 (or AT#F) allows no fallback when on-line. AT#F1 allows the Modem to fallback (based on the error rate or if three retrains have occurred within a two minute period) from 33.6K to 31.2K to 28.8K to 26.4K to 24K to 21.6K to 19.2K to 16.8K to 14.4K to 12K to 9.6K to 4.8K bps. The AT#F2 command enables incremental fall back from 33.6K to 4.8K, but also enables incremental fall forward (from 4.8K to 33.6K) if the phone line improves. AT#F2 is the factory default setting.

Enable/Disable Lowspeed Fast Connect $FC (336+ Only)

With the Series II Modem 336+ (MD1640A), entering

AT$FC0&W0<CR> sets up the data pump so that it will not transmit a 5 second 2100 Hz signal. Entering AT$FC0&W0<CR> allows the modem to transmit a 5 second 2100 Hz signal and is the factory default.

Cleardown at Disconnect &CD

The &CD command is used for control of cleardown at disconnect in V.32, V.32bis, V.34 and V.34 enhanced modes.

A cleardown usually adds 1-2 seconds to the time it takes for the modem to go on-hook after a disconnect. A cleardown makes a disconnect by the remote modem easier to detect and a subsequent re-connection more likely. Enter AT&CD0&W0<CR> to execute a cleardown at disconnect (default); and enter AT&CD1&W0<CR> to disable the cleardown function.

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Black Box MD1640A, MD1641A manual Fallback Modes When On-Line #F, Enable/Disable Lowspeed Fast Connect $FC 336+ Only

Contents

Series II Modem Series II Modem 336+ Series II Modems Series II Intelligent DATA/FAX Modems Contents Command Mode Manual Dial and Automatic Answer Registers Callback Security and Remote ConfigurationModem Testing Other Appendixes DIP-Switch SettingsAppendix a Troubleshooting Introduction How To Use This Manual Introduction and Description Installation and Connection Software ConfigurationAT Command Mode Operation Manual Dial and Automatic Answer DIP-Switches Callback and Remote ConfigurationTesting Your Modem What is in Your Modem Package? Modem Features Fax Features Technical Specifications Mode of Operation Intelligent FeaturesCommand Buffer Modulation Fax Carrier FrequenciesLease Line Restoral Carrier Frequencies Connectors DiagnosticsIndicators Operating Temperature Power Modem LED Indicators Introduction and Description Controls on PC Board Installation and Connection Safety Warnings Installation Series II Modem 336 MD1641A Connections Series II Intelligent DATA/FAX Modems Is Your Series II Modem Ready for Use? Operating Your Series II Modem Answer/Originate Voice/Data Toggle Switch Simple Operations Introduction Serial Port Limitations Software Configuration How Can You Identify Your Uart Type? 16550 Uart and Windows COMnFIFO=1 Configuring Your Software Configuring Software for Your Modem Changing Default Parameters PC Initialization StringsAT &F X4 S0=0 M AT &F X4 S0= 2 M Other Parameters Macintosh InitializationAT &F X4 M AT &F X4 &E5 &E13 &D0 M Configuring Software for Your Computer Configuring Software for the Remote SystemSoftware Configuration AT &F9 &W0 CR When to Disable Data Compression Terminal EmulationFile Transfer Protocols User Guide for Series II Modems AT &F S0=0 X4 &E0 M Disabling Error CorrectionAT &F S0=0 X4 &E14 M Manual Dial and Automatic Answer Dialing/On-Line/Answering Series II Intelligent DATA/FAX Modems Automatic Leased Line Restoral Operation 336+ Only Manual Dial Backup Call Termination 336+ OnlyDial Backup and Leased Line Restoral 336+ Only Series II Intelligent DATA/FAX Modems Dial-Up Operation 336+ Only Manual Call Origination Automatic Answering Manual Answering Handshaking Details Call Termination Abort Timer Command Mode AT Command Editing Command Mode Functional Modes Summary of AT Commands Functional Modes Memorize Phone Numbers #L0 #L1#L2 #L3 E14 E15$BA1 +++ATCR Result Codes Sr?Sr= #RCBNxx Q0 Series II Result Codes Q1 Standard AT Result Codes Continuous Redial a or Dialing Commands Dialing Action CommandsDial Command D Dialing a Stored Number N DTR Dialing $D Pulse or Tone Dial P or T Dial Modifier CommandsVoice/Data Dialing $VD Long Space Disconnect Y Set Pulse Dial Ratios &PAutomatic Pauses in Dialing Wait for New Dial-Tone W Return to Command Mode after Dial Command ExecutionReverse the Mode of Operation R Flash On Hook Calling Card Detect Tones $Quiet Answer @ ATDT101099907247465500$0123 4567 8910 Phone Number Memory Commands Storing Phone Numbers D...NNumber Linking NN ATX4&E1&E5&E13&E15DT17247465500N3 Listing Numbers Stored in Memory L Configuration and Default Storage Commands Loading Factory Defaults &F Unix Uucp Spoofing $SP Modem Reset Z32terbo Enable/Disable #V 336 Only Async/Sync Mode Switching &M Synchronous Transmit Clock Select &X Command Response Result Code Commands Echo Command Mode Characters EResult Codes Enable/Disable and No Response Answer Q Chap 5 Command Modeter Result Codes Verbose/Terse Result Codes Basic and Extended and Call Progress Selection Command Mode Phone Line Conditioning Commands Enable/Disable Trelis Coded Modulation #TGuard Tones &G Phone Line Monitoring Speaker M Cleardown at Disconnect &CD Fallback Modes When On-Line #FEnable/Disable Lowspeed Fast Connect $FC 336+ Only Carrier Detect Control &C 7 RS232C Interface Control CommandsAuto Speed Detect #A Data Terminal Ready Control &D Clear to Send Control &R Error Correction Commands Data Set Ready Control &SCTS/RTS Interaction Control &RF DSR/CD Interaction Control &SF Normal Mode &E0 Auto-Reliable Mode &E1 Reliable Mode &E2 Mode Select #LOriginate Mode Answer Mode Enable/Disable Auto Reliable Fallback Character $F Auto-Reliable Buffering $A Retransmit Count $R Flow Control Commands Error Correction/300bps $E Hardware Flow Control &E4 Modem Terminal Xon/Xoff Flow Control &E5 Xon/Xoff Pass-Through &E7 Hewlett-Packard ENQ/ACK Pacing &E9 Normal Mode Modem Flow Control On &E11Send Xon/Xoff Characters #X Terminal/Computer Initiated Pacing &E13 Maximum Block Size &BS Asynchronous Word Length Selection $EB 336 Only Parity Selection #P #X0 = #X1 = Normal Mode Modem Flow Control Commands Speed Conversion CommandsEnq/Ack Pacing Commands Speed Conversion $BA Modem Baud Rate $MB Serial Port Baud Rate $SB Immediate Action Commands Help Screens $H Inquiry for Product Code Windows 95 Autodetect Inquiry Listing S-Register Values L6 Listing On-Line Diagnostics L8Listing Current Operating Parameters L5 L7 On-line diagnostics information On or Off Hook H Break Atcr Exiting Command Mode, Going Back On-Line O Line Probe CommandsForce Answer Mode a Format of Line Probe Graph or Table Commands DF0 Immediate Action Line Probe CommandsDP1 DF1 Number of Rings Until Modem Answers Rings Which Have Occurred Line Feed Character Escape Code CharacterReturn Character Time for Carrier Abort Timer Backspace CharacterWait Time for Dial Tone Pause Time for Comma S10 Carrier Loss Disconnect Delay Time Carrier Detect Response Time S11 Tone Dialing Tone Spacing and Duration S13 Remote Configuration Escape CharacterS15 Callback Time Delay S18 Automatic Leased Line Restoral 336+ Only S16 Callback AttemptsS17 Changing Break Time S25 DTR Dropout Time S19 Dial-Back Timer 336+ OnlyS24 PBX/CBX Disconnect Drop Time for DSR/CTS/CD S26 Failed Password Attempts S29 Local Inactivity Timer S30 Inactivity Timer S32 Time Elapse for Escape Sequence S48 Program V.34bis Connect Speeds S36 Time Between DTR Inactive and Modem Off-HookS37 Time Between DTR Active and Modem On-Hook Reading and Assigning S-Register Values Examples of Assigning Values ATS0=30S3?, and ATS7=55S7? AT Command and S-Register SummaryExamples of Reading Values Callback Security Remote Configuration Callback Feature Description Callback Security and Remote Configuration Remote Configuration Description Error To change your Remote Configuration feature status To turn your modems Callback Security feature on and off To set parity of the password/message prompt AT#IxxxxxxxxxxCR xxxxxxxxxx from Table AT#DB2CRÊorÊAT#DB1CRAT#CBN0xxxxxxxxxxCR AT#CBN1xxxxxxxxxxCR AT#SyyyyyyyyyyCR yyyyyyyyyy from Table Callback Operational Sequence Procedures Password Remote Configuration Procedures Remote Configuration Operation Procedures StepProcedure Callback Security Enable/Disable #DB Remote Configuration and Callback Security AT CommandsAssign Passwords for Callback Phone Numbers #CBN Change Login Password #I Change Setup Password #SErase Callback Password #RCBNxx Erase Callback Phone Number #RDNxx Remote Configuration/Callback Security S-Registers Remote Configuration Character S13Callback Time Delay S15 Callback Attempts S16 Failed Password Attempts S26 Local Inactivity Timer S29 Modem Testing Modem Testing Local Analog Loopback Test/V.54 Loop Digital Loopback Test/V.54 Loop 2 Local/Manual Digital Loopback Test local/manual 119 Digital Loopback Test/V.54 Loop 2 Remote/Automatic Digital Loopback Test remote/automatic Back-to-Back Test 122 Synchronous Mode Testing Local Analog Loopback Test Synchronous Mode Digital Loopback Test Local/Manual Synchronous Mode Digital Loopback Test Remote/Automatic Synchronous Mode 126 DIP-Switch Settings DIP-Switch Option Settings Series II Modem 336+ MD1640A PC Board 129 Switch #4 AS/400 Mode Synchronous Mode/Leased Line/Dial-Up 130 131 132 133 134 135 Speaker Volume Control Recording Option Configurations Function Position Effect DIP Switches #13-16 AT vs. Series II Result Codes Possible Causes and Solutions None of the LEDs Light When the Modem Is On Modem Does Not Respond to Commands 141 Modem Dials But Cannot Make a Connection 143 Modem Cannot Connect When Answering Modem Disconnects While On-line File Transfer Is Slower Than It Should Be Am Losing Data Am Getting Garbage Characters on the Monitor Contacting Black Box Recording Modem Information Modem Model No Making the Call Shipping and Packaging Upgrading the Series II Modem’s Firmware Tone Dial Frequencies 697 770 852 941 1209 Digits 1336 1633 Appendix B Dial Pulse and Tone-Dial FrequenciesDial Pulses Appendix C Command Summary CommandDescription $An BSn $BAnCDn DsNd $Dn DFnDPn $En $EBn#Fn $FCn Command Values Description $Hn NdNe #Ln$MBn RFn #Pn$Rn Sr=n $SBnSFn $SPn #Tn $VDn 160 #Xn Callback Security/Remote Configuration Command Summary Command Description #DBn#CBNyyxxxxxx + Dxxxxxx???Nxx Password Command Summary 25bis Commands DIP-Switch Condition Effect Appendix D DIP-Switch SummaryAsynchronous Mode Synchronous Mode 166 Appendix E S-Register Summary Appendix E S-Register Summary S13 S15 S24 S36 Digit Words Appendix F Result Code SummaryEffect 172 Appendix F Result Code Summary Delayed and Forbidden Numbers Appendix G V.25bis Operation Appendix G V.25bis Operation 25bis Operation 25bis DIP-Switches 25bis Set-Up and Initialization 25bis Mode AT Commands 25bis AT Commands 25bis Responses Result Codes Enable/Disable V.25bis Mode $V Command Change Serial Baud Rate CSP Command Dial Phone Number Provided CRN Command Disregard or Connect to Incoming Calls DIC or CIC Command Listing Delayed Phone Numbers RLD CommandListing Forbidden Phone Number RLF Command DTR Dialing $D Command ITU V.25bis Country Specific Information Italy Austria France Belgium Singapore Appendix H Series II modem cables Appendix H Series II Modem Cables 188 Appendix I RS232C Interface Specifications Appendix I RS232C Interface Specifications Received Data Pin 3, RD BB Request To Send Pin 4, RTS CADirection to modem Direction from modem Signal Ground Pin 7, SG AB Clear To Send Pin 5, CTS CBData Set Ready Pin 6, DSR CC Data Carrier Detect Pin 8, CD CF Data Terminal Ready Pin 20, TR or DTR CD Transmit Clock Pin 15, TC DBReceive Clock Pin 17, RC DD External Transmit Clock Pin 24, XTC Ring Indicator Pin 22, RI CETerminal Busy Out of Service Pin 25, OOS Appendix J Regulatory Information FCC and IC EMI/RFI Statements Appendix J Regulatory Information FCC Part 68 Regulations for Telephone-Line Interconnection 196 Canadian Limitations Notice 197 Copyright 2000. Black Box Corporation. All rights reserved