Multi-Tech Systems MT3334HD8 #Fn Fallback Modes, Gn Guard Tones, Hn Busy-Out After Disconnect

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MT3334HD8 User Guide

#Fn Fallback Modes

n = 0, 1, or 2 Default: #F2

The #F command controls whether the modem will fall back to a lower speed because of an unacceptable error rate. If line conditions deteriorate, the modem has the ability to fall back from its original speed to the next lower speed when operating in V.34, V.32bis, or V.32 mode. If the error rate becomes too great, the modem performs a retrain at the next lower speed. If, after the retrain, the error rate is still too high, the modem performs a retrain at the next lower speed, down to 4800 bps.

If the modem returns online at the original speed after the first retrain, the modem starts a counter and a timer. If three retrains occur within a two-minute period, the modem falls back to 4800 bps.

The fallback and fall-forward speeds for the modem are 33.6K, 31.2K, 28.8K, 26.4K, 24.0K, 21.6K, 19.2K, 16.8K, 14.4K, 12K, 9.6K, and 4.8K bps.

#F0 (or #F) disables fallback when online.

#F1 lets the modem fall back from the starting speed to a low speed of 4800 bps in 2400 bps decrements.

#F2 lets the modem fall back when line conditions deteriorate, but also lets it fall forward in 2400 bps increments if line conditions improve.

&Gn Guard Tones

n = 0, 1, or 2

Default: &G0 (models outside U.K.) or &G2 (U.K. models only)

The &G command is used to control the presence or absence of guard tones from the transmitter when in answer mode at either 1200 or 2400 bps. Guard tones are used in Europe and other areas to allow the modem to function in the telephone systems. Guard tones are not used in the United States. U.K. models are locked at &G2 (1800 Hz guard tone).

&G0 disables ITU-T guard tones.

&G1 enables ITU-T 550 Hz guard tone.

&G2 enables ITU-T 1800 Hz guard tone.

*Hn Busy-Out After Disconnect

n = 0 or 1 Default: *H0

The *H1 command causes the MT3334HD8 to remain out of service and return a busy signal until configuration from the CommPlete Communication Server’s dedicated management console has finished. If no configuration option is set on the dedicated management console, the MT2834MR remains out of service for ten seconds after disconnect. Register S94 controls the length of the out-of-service, or busy-out, time (see Chapter 4).

*H0 disables busy-out after disconnect.

*H1 enables busy-out after disconnect.

&Pn Set Pulse-Dial Ratios

n = 0 or 1

Default: &P0 (Models outside U.K.) or &P1 (U.K. models only)

The &P command sets the time ratios between the open (break) and closed (make) states of dialing pulses. U.K. models are locked to &P1 (67:33 ratio). See Appendix B for more dial pulse information.

&P0 sets a pulse dial ratio of 60 ms break to 40 ms make.

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CommPlete Communications Server

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Contents MT3334HD8 Modem User Guide Multi-Tech Systems, Inc Woodale Drive Mounds View, Minnesota CommPlete Communications Server FCC Fax Warning Canadian Limitations NoticeTable of Contents Testing the MT3334HD8 Warranty, Service, and Technical SupportAppendix D Appendix FIntroduction LED Indicators Power SuppliesIntroduction Manual OrganizationInstallation Technical Specifications Data Rates ModemIntroduction 2400 & 1200 bps MT3334HD8 User Guide Power Installation Safety Warnings MT3334HD8 modem cardPre-Installation Notes Installation ProcedurePage AT Commands Modes of Operation Working with AT CommandsCommand Structure Command Editing AT Commands by Function $BA Dialing Commands Dial Modifier CommandsDs Dial Continuous RedialPulse or Tone Dialing Wait for New Dial ToneRn Reverse Originate/Answer Mode Return to Command Mode After DialingDialing Pause Flash On-HookPhone Number Memory Commands @ Quiet AnswerCall Card Tone Detect DsNd Store a Phone NumberConfiguration Storage and Recall Commands Wn Store ConfigurationNdNe Number Linking List Stored Telephone NumbersReset Modem Modem Response Result Code CommandsFn Load Default Configuration Echo Command Mode Characters Result Codes Verbose/Terse Online Connection Commands An Answerback#An Auto Speed Detection Bn Answer ToneDTn Dtmf Detection DCn AT Command ControlCDn Cleardown at Disconnect #Fn Fallback Modes Gn Guard TonesHn Busy-Out After Disconnect Pn Set Pulse-Dial Ratios#Tn Trellis-Coded Modulation RDn Square Wave Ring Detect$Tn Calling Tone Commands Fn Echo Canceler Frequency Offset CompensationYn Long Space Disconnect RAn Asymmetric Bit RateDn Data Terminal Ready Control RS-232 Interface CommandsCn Carrier Detect Control Rn Clear to Send Control Sn Data Set Ready ControlRFn CTS/RTS Interaction Control SFn DSR/CD Interaction ControlError Correction and Data Compression Commands En Error Correction Modes#Ln V.42 Error Correction Modes En Data Compression$An Auto-Reliable Buffering $En V.42 Error Correction at 300 bps$Fn Auto-Reliable Fallback Character Enable/Disable $Rn Retransmit Count Speed Conversion Commands$BAn Baud Adjust $MBn Modem Baud Rate $SBn Serial Port Baud RateImmediate Action Commands Repeat Last CommandInquire Product Code L5, L7 List Current Operating ParametersFlow Control Commands E3 Flow Control Disable En Non-Error Correction Mode Flow ControlE4 Hardware Flow Control E5 XON/XOFF Flow ControlEn Pacing Computer-Initiated Flow Control #Xn Number of Xoff Characters SentForce Answer Mode Escape Sequences+++ATCR In-Band Escape Sequence Breakatcr Out-of-Band Escape SequenceRemote Configuration Commands Atcr Remote Configuration Escape Sequence#Ixxxxxx Change Login Password Go Back OnlineLine Probe Commands #Syyyyyy Change Setup PasswordDPn Read Line Probe Data DFn Format Line Probe DataDiagnostic Commands Tn Respond to Remote Digital Loopback SignalRP Immediate Line Probe Ln Display Line Probe DataUn Loopback Test Modes MT3334HD8 User Guide Registers Registers S0 Number of Rings Until Modem AnswersS1 Ring Count S2 Escape Code CharacterS7 Time for Carrier Abort Timer S4 Line Feed CharacterS5 Backspace Character S6 Wait Time for Dial ToneS10 Carrier Loss Disconnect Delay Time S13 Remote Configuration Escape CharacterS9 Carrier Detect Response Time S11 Tone Dialing Spacing and DurationS30 Inactivity Timer S34 Command Buffer Length After Online Escape SequenceS24 PBX/CBX Disconnect Drop Time for DSR/CTS/CD S25 DTR Dropout TimeS94 Out-of-Service Time S37 DTR Busy-In TimeS43 Force V.34 Connect Speed S48 Maximum V.34 Connect SpeedAT Commands that Affect S-Registers Reading and Assigning S-Register ValuesExamples of Assigning Values Examples of Reading ValuesAT&E2$SP1#L3$R0$MB19200$SB115200$EB1S0=10&W0CR Testing the MT3334HD8 Test procedure Local Analog Loopback Test V.54 LoopTesting the MT3334HD8 Remote Digital Loopback Test V.54 LoopDial the remote modem and establish your online connection Local Digital Loopback Test V.54 Loop Local digital loopback testPage Warranty, Service, and Technical Support Limited Warranty ServiceTechnical Support Recording Product InformationDownloading a File Multi-Tech BBSLogging onto the Multi-Tech BBS About CompuServe Reading a MessageLeaving a Message BulletinsAbout the Multi-Tech Fax-Back Service About the InternetUsing FlashPro to Upgrade Firmware Upgrading the MT3334HD8 FirmwareMT3334HD8 User Guide Appendixes Appendix a Ascii Conversion Chart Ctrl Code HEX DECTone Dial Frequencies Appendix B Dial Pulses and TonesDial Pulses Figure B-2. Standard Dtmf frequencies Appendix C Result Code Summary Multi-Tech Result Codes &Q0Standard AT Result Codes &Q1 Register Unit Range Default Description Appendix D S-Register SummarySets fixed V.34 connect speed = 28800 bps Appendix E AT Command Summary ReturnCDn AT Command Summary $Fn Command Values Description Command Values Description $MBn RAn Command Values Description SFn Command Values Description #Vn Breakatcr Setup Appendix F Remote ConfigurationBasic Procedure Changing the Passwords Changing the Remote Escape CharacterIndex MT3334HD8 User Guide Index Long space break Pacing, 36, 37, 38 enable/disable, 38 ENQ/ACK Commands Loopback tests, 42, 43, 54, 56 tone detection
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