Multi-Tech Systems MT3334HD8 manual E3 Flow Control Disable, E4 Hardware Flow Control

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3 AT Commands

$EB0 enables a 10-bit format It automatically detects parity when an AT command is issued.

$EB1 enables an 11-bit format.

&E3 Flow Control Disable

The &E3 command completely disables data flow control initiated by the modem.

&E4 Hardware Flow Control

Factory default. The &E4 command enables the modem’s use of the Clear to Send (CTS) signal on the RS- 232/V.24 interface to regulate data flow. When CTS drops, data flow is suspended until the signal goes high again. This method of flow control works in conjunction with pacing (i.e., computer-initiated flow control), which uses the Request to Send (RTS) signal on the RS-232/V.24 interface. Hardware flow control cannot be enabled unless an active error correction protocol is selected.

&E5 XON/XOFF Flow Control

XON/XOFF flow control is an in-band method of data flow regulation used by the modem or computer (i.e., by flow control or pacing). If you issue the &E5 command to the modem, it will respond to XON/XOFF pacing, and use XON/XOFF characters as its own method of flow control to the computer.

In-band data regulation means that the XON and XOFF characters (^Q and ^S, respectively) are inserted into the stream of data rather than using separate control lines. When an XOFF character is detected, the data stream is suspended until an XON character is detected. The drawback to using this method of pacing is that some files may contain these characters. If such a file is transferred using a modem, the file transfer can be suspended indefinitely.

&En XON/XOFF Pass-Through

n = 6 or 7 Default: &E6

When XON/XOFF pacing is active, the local modem has two options regarding the XON and XOFF characters. It can respond to and discard the characters from the computer, or it can respond to the characters and pass them through the datacomm link to the remote modem, thereby pacing the remote modem as well.

&E6 causes the modem to respond to and discard the XON and XOFF characters.

&E7 causes the modem to respond to the characters and pass them through the data link to the receiving modem.

&En Hewlett Packard ENQ/ACK Pacing

n = 8 or 9 Default: &E8

If the MT3334HD8 is used with Hewlett Packard (or compatible) equipment, it can be configured to respond to ENQ/ACK pacing as a complement to any other form of active flow control or pacing. In that case, pacing from the Hewlett Packard equipment is processed according to the HP protocol.

&E8 causes the modem to ignore ENQ/ACK pacing.

&E9 causes the modem to respond to the ENQ (^E) and ACK (^F) characters.

&En Non-Error Correction Mode Flow Control

n = 10 or 11 Default: &E10

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Contents MT3334HD8 Modem User Guide Multi-Tech Systems, Inc Woodale Drive Mounds View, Minnesota CommPlete Communications Server Canadian Limitations Notice FCC Fax WarningTable of Contents Appendix F Testing the MT3334HD8Warranty, Service, and Technical Support Appendix DIntroduction Manual Organization LED IndicatorsPower Supplies IntroductionInstallation Data Rates Modem Technical SpecificationsIntroduction 2400 & 1200 bps MT3334HD8 User Guide Power Installation MT3334HD8 modem card Safety WarningsInstallation Procedure Pre-Installation NotesPage AT Commands Command Structure Working with AT CommandsModes of Operation Command Editing AT Commands by Function $BA Continuous Redial Dialing CommandsDial Modifier Commands Ds DialWait for New Dial Tone Pulse or Tone DialingFlash On-Hook Rn Reverse Originate/Answer ModeReturn to Command Mode After Dialing Dialing PauseDsNd Store a Phone Number Phone Number Memory Commands@ Quiet Answer Call Card Tone DetectList Stored Telephone Numbers Configuration Storage and Recall CommandsWn Store Configuration NdNe Number LinkingFn Load Default Configuration Modem Response Result Code CommandsReset Modem Echo Command Mode Characters Result Codes Verbose/Terse Bn Answer Tone Online Connection CommandsAn Answerback #An Auto Speed DetectionCDn Cleardown at Disconnect DCn AT Command ControlDTn Dtmf Detection Pn Set Pulse-Dial Ratios #Fn Fallback ModesGn Guard Tones Hn Busy-Out After Disconnect$Tn Calling Tone RDn Square Wave Ring Detect#Tn Trellis-Coded Modulation RAn Asymmetric Bit Rate CommandsFn Echo Canceler Frequency Offset Compensation Yn Long Space DisconnectCn Carrier Detect Control RS-232 Interface CommandsDn Data Terminal Ready Control SFn DSR/CD Interaction Control Rn Clear to Send ControlSn Data Set Ready Control RFn CTS/RTS Interaction ControlEn Data Compression Error Correction and Data Compression CommandsEn Error Correction Modes #Ln V.42 Error Correction Modes$Fn Auto-Reliable Fallback Character Enable/Disable $En V.42 Error Correction at 300 bps$An Auto-Reliable Buffering $BAn Baud Adjust Speed Conversion Commands$Rn Retransmit Count $SBn Serial Port Baud Rate $MBn Modem Baud RateL5, L7 List Current Operating Parameters Immediate Action CommandsRepeat Last Command Inquire Product CodeFlow Control Commands E5 XON/XOFF Flow Control E3 Flow Control DisableEn Non-Error Correction Mode Flow Control E4 Hardware Flow Control#Xn Number of Xoff Characters Sent En Pacing Computer-Initiated Flow ControlBreakatcr Out-of-Band Escape Sequence Force Answer ModeEscape Sequences +++ATCR In-Band Escape SequenceGo Back Online Remote Configuration CommandsAtcr Remote Configuration Escape Sequence #Ixxxxxx Change Login PasswordDFn Format Line Probe Data Line Probe Commands#Syyyyyy Change Setup Password DPn Read Line Probe DataLn Display Line Probe Data Diagnostic CommandsTn Respond to Remote Digital Loopback Signal RP Immediate Line ProbeUn Loopback Test Modes MT3334HD8 User Guide Registers S2 Escape Code Character RegistersS0 Number of Rings Until Modem Answers S1 Ring CountS6 Wait Time for Dial Tone S7 Time for Carrier Abort TimerS4 Line Feed Character S5 Backspace CharacterS11 Tone Dialing Spacing and Duration S10 Carrier Loss Disconnect Delay TimeS13 Remote Configuration Escape Character S9 Carrier Detect Response TimeS25 DTR Dropout Time S30 Inactivity TimerS34 Command Buffer Length After Online Escape Sequence S24 PBX/CBX Disconnect Drop Time for DSR/CTS/CDS48 Maximum V.34 Connect Speed S94 Out-of-Service TimeS37 DTR Busy-In Time S43 Force V.34 Connect SpeedExamples of Reading Values AT Commands that Affect S-RegistersReading and Assigning S-Register Values Examples of Assigning ValuesAT&E2$SP1#L3$R0$MB19200$SB115200$EB1S0=10&W0CR Testing the MT3334HD8 Local Analog Loopback Test V.54 Loop Test procedureRemote Digital Loopback Test V.54 Loop Testing the MT3334HD8Dial the remote modem and establish your online connection Local digital loopback test Local Digital Loopback Test V.54 LoopPage Warranty, Service, and Technical Support Service Limited WarrantyRecording Product Information Technical SupportLogging onto the Multi-Tech BBS Multi-Tech BBSDownloading a File Bulletins About CompuServeReading a Message Leaving a MessageAbout the Internet About the Multi-Tech Fax-Back ServiceUpgrading the MT3334HD8 Firmware Using FlashPro to Upgrade FirmwareMT3334HD8 User Guide Appendixes Ctrl Code HEX DEC Appendix a Ascii Conversion ChartDial Pulses Appendix B Dial Pulses and TonesTone Dial Frequencies Figure B-2. Standard Dtmf frequencies Multi-Tech Result Codes &Q0 Appendix C Result Code SummaryStandard AT Result Codes &Q1 Appendix D S-Register Summary Register Unit Range Default DescriptionSets fixed V.34 connect speed = 28800 bps Return Appendix E AT Command SummaryCDn AT Command Summary $Fn Command Values Description Command Values Description $MBn RAn Command Values Description SFn Command Values Description #Vn Breakatcr Basic Procedure Appendix F Remote ConfigurationSetup Changing the Remote Escape Character Changing the PasswordsIndex 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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