Multi-Tech Systems MT2456SMI22 manual Transmit Flow Control Thresholds, +Itf?

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Chapter 4 - V.22bis Commands

+ITF

Transmit Flow Control Thresholds

The +ITF command determines the flow control thresholds used by the modem for transmit data from the DTE. This optional compound parameter allows the DTE to determine the input buffer size in the modem for data on circuit 103 (transmit data) from the DTE, to control the thresholds used for flow control of such data, and to control how often the modem reports to the DTE the number of octets in this buffer. The DTE can adjust its own thresholds for flow control of data on circuit 104 (received data) from the modem.

Syntax +ITF=[<off>[,<on>[,<report_period>]]]

Defined Values

<off> Determines the threshold, in octets, above which the modem will generate a flow off signal. Applicable in Synchronous Access and Frame Tunneling modes. Default <off> value is 255.

For the <on> and <off> subparameters, the input buffer is assumed to reside between the modem’s V.24 interface and the Synchronous Access protocol layer; i.e., the buffer count includes all octets, including EM codes, received from the DTE, with the exception of DC1 and DC3 if these are used to signal <modem-by- DTE> flow control.

The modem returns the ERROR result code if the DTE specifies that the <off> subparameter be set to a value less than or equal to the <on> subparameter; in this case, the current parameter value settings are not modified.

<on> Determines the threshold, in octets, below which the modem will generate a flow on signal. Applicable in Synchronous Access and Frame-Tunneling modes. Default <on> value is 64.

<report_period> Not supported. A fixed value of zero is used and reported.

Reporting Selected Options

The modem sends a string of information text to the DTE consisting of selected options in response to the following command:

+ITF?

The response is:

+ITF: <off>,<on>,<report_period> Example:

+ITF?

+ITF: 255,64,0 Default values

Reporting Supported Options

The modem sends a string of information text to the DTE consisting of supported options in response to the following command:

+ITF=?

The response is:

+ITF: (list of supported <off> values),(list of supported <on> values),(list of supported <report_period> values) Example:

+ITF=?

+ITF: (0-255),( 0-255),(0)

The maximum reported <off> value is the input transmit data buffer level at which the modem signals a transmit data overrun indication to the DTE.

Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide

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Contents SocketModem PN S000281A, Version a Country By Email By PhoneContents Product Description Specifications Product DescriptionTechnical Specifications Speed ConversionPhysical Dimensions Maximum Component HeightPin Configurations Pin Descriptions3V DC Power Handling Precautions 3V and 5V Serial SocketModemInput High Input Low Outputs Output High Output LowGeneric Modem Control Commands DTE/DCE CommandsCall Control Commands Modulation Control CommandsError Control and Data Compression Commands Synchronous Access Mode CommandsFast Connect Command Line Side Device Commands22bis Generic Modem Control Commands Soft Reset and Restore ProfileOperating Mode +VCID Caller ID CID+GCI Country of Installation IdentificationRestore Factory Configuration Profile ProcedureLocal Analog Loopback Test Load to Internal RAM22bis DTE/DCE-Modem Interface commands Command EchoQuiet Result Codes Control Result Code FormConnect Ring No Carrier Error No Dial Tone Busy No Answer Extended Result CodesShort Form Long Form Value in ATXn Command Rlsd OptionResult Codes OK 0 or DTR Option+IFC DTE-Modem Local Flow Control RTS/CTS Option\G Modem-to-Modem Flow Control XON/XOFF EM Shielding Data +IBC In Band CommandsEntering and Exiting In Band Active State Band Processing of AT Commands Command Hex Codes Description Supported DTE-to-DCE CommandsSupported DCE-to-DTE Commands Dial Modifiers 22bis Call Control CommandsDial Set Tone Dial Default Result Code Set Pulse Dial DefaultReturn to On-Line Data Mode Speaker VolumeDisplay Current Configuration and Stored Profiles MSpeaker ControlSelect Guard Tone Select Pulse Dial Make/Break Ratio\V Single Line Connect Message Enable Report Line Signal LevelReport Line Signal Quality Display Blacklisted NumbersDisplay Delayed Numbers NO. Phone Number -DELAYBehavior in Data Mode Syntax *D Example+VDR Distinctive Ring +PCW Call Waiting EnableReporting Selected Values 22bis Modulation Control Commands Table of +MS Command Supported Rates+MS Modulation Selection SyntaxEnable/Disable Line Quality Monitor and Auto-Retrain ITU-T or Bell22bis Error Control and Data Compression Commands +ESR Selective Repeat+ETBM Call Termination Buffer Management \B Transmit Break to RemoteResult Codes OK 0 to 5 Error Otherwise Break Control22bis Synchronous Access Mode Commands +ESA Configure Synchronous Access SubmodeReporting Selected Options +ESA?Transmit Flow Control Thresholds +ITF?Syntax $Fn Defined Values 22bis FastConnect Command$F Fast Connect Control 22bis Line Side Device Commands Threshold Adjustments for Telephony ExtensionTRV Tip and Ring Voltage Measurement Response22bis S-Parameters Read/Write S-ParameterAscii Summary of S-Parameter DefaultsRegister Function Range/Units Default S0 Number of Rings to Auto-Answer S1 Ring CounterS2 Escape Character S3 Carriage Return CharacterS8 Pause Time For Dial Delay S10 Lost Carrier To Hang Up DelayS12 Escape Prompt Delay EPD S9 Carrier Detect Response TimeS16 Test Mode Bit Mapped Options Status S19 ReservedS20 Reserved S21 V.24/General Bit Mapped Options StatusS24 Sleep Inactivity Timer S25 Delay To DTR OffS26 RTS to CTS Delay S22 Speaker/Results Bit Mapped Options StatusS30 Disconnect Inactivity Timer S27 Bit Mapped Options StatusS28 Bit Mapped Options Status S29 Flash Dial Modifier TimeS38 Delay Before Forced Hang Up S36 Lapm Failure ControlS37 Desired Line Connection Speed S39 Flow Control Bit Mapped Options StatusS41 General Bit Mapped Options Status S48 V.42 Negotiation ActionS82 Break Handling Options S86 Call Failure Reason CodeS91 Pstn Transmit Attenuation Level S95 Extended Result Codes Control22bis Result Codes Table of Result Code DefinitionsCode Message Meaning Connect75TX/1200RX Is enabled Block Diagram Figure A-1. Serial Test/Demo Board Block DiagramProduct Safety and EMC Approvals Country CertificationsCountry Country Code More plannedRegulatory Design Considerations Hardware ConsiderationsSafety SocketModem Placement Qty Name DescriptionTelecom Requirements for the United States ComplianceMulti-Tech Systems, Inc. Compliance Label Content and Format Label Physical CharacteristicsOther Label Requirements Telecommunications Regulations for CanadaLabeling Continuity and Changes New Zealand Telecom Warning Notice Industry CanadaSouth African Statement EMC, Safety, and R&TTE Directive ComplianceInternational Modem Restrictions Index Index
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