Intel 536EX manual 1.3Modem Connection Overview, Intel Confidential, Introduction

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1.3Modem Connection Overview

Introduction

1.3Modem Connection Overview

The DCE (modem) operates in one of two states: command or online. In each state, both data and commands (including DCE responses) are transferred through the UART THR (Transmit Holding register) and the RBR (Receiver Buffer register).

The modem defaults to the command state. In the command state, the DTE (host) communicates to the modem through AT commands and S-registers. AT commands are character strings that help guide modem operation. S-registers are internal modem registers that the DTE can access. The S- registers contain modem status and configuration information. Many of the AT commands indirectly affect the contents of the S-registers. The AT command set and S-registers are divided into the following modes: Group 3 fax, data, V.44/V.42 bis/V.42/MNP, and voice. Note that supported AT commands are firmware revision-dependent (that is, not all commands are supported by all modem models or all firmware revisions).

All command lines sent to the modem, except for A/, must be preceded by an ‘AT’ (which stands for ‘attention’) and terminated by the contents of S-register S3 (typically a carriage return <CR>). The ‘AT’ prompts the modem to receive a command line from the DTE. A <CR> informs the modem that the entire command string has been transmitted and that the modem should start processing all the commands within the command line.

A command line may include one or more AT commands that may or may not be separated by a space. AT commands may be either upper- or lower-case characters, but all characters for a given command must use the same case. If there are multiple commands in a line, a semicolon (;) must be placed after each fax or voice command. The modem can be configured to send back (echo) to the DTE any data that the DTE sends to the modem (while in command state only). The last command may be repeated by typing A/ without using a carriage return. Each command line may include up to 80 characters and spaces.

Examples of AT command strings:

ATS1?<CR>

A/

AT &C1 &D2 +FCLASS=? <CR>

AT &C1 &D2 +FCLASS=?; S0=1 <CR>

The modem provides status information to the DTE in the form of response codes. These response codes can be expressed in text or numeric form. The supported response codes are provided in Table 4 on page 12.

Examples of modem responses:

+MCR: V90

+MRR: 28800

CONNECT 50666

In the online state, the DCE is off-hook and communicating with a remote modem. Any data sent from the DTE to the DCE is transmitted to the remote modem. Similarly, any data that the DCE receives from the remote modem is transmitted to the DTE.

Note: In the online state, the DCE does not ‘echo-back’ any of the data that the DTE sent to the DCE.

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536EX Chipset Developer’s Manual

Intel Confidential

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Contents Developer’s Manual 536EX ChipsetJanuary Intel Confidential 536EX Chipset Developer’s ManualContents ContentsFigures Tables Revision Revision HistoryDate DescriptionIntroduction 1.1Controllerless Modem Driver OverviewUser applications Figure 1. WDM Driver Block Diagram1.1.2Windows 95 and Windows Kernel - ring0Figure 2. VxD Mini Port Driver Block Diagram 1.2V.90/V.92 and V.34 Data Modes1.3Modem Connection Overview Table 2. DCE-to-DCEData Rates for Each Mode Table 1. DTE-to-DCEData Rates for Each ModeTable 3. DCE-to-ISPData Rates for V.90 Mode 1.4.1Sending Commands Table 4. DTE-ModemData Rate Response Codes1.4.2AT Escape Sequences 1.4.3Dial ModifierAT Command Summary Tables AT Command Summary TablesTable 5. Data Mode Command Summary Table 5. Data Mode Command Summary Continued Result code type Intel Confidential Generate data mode calling tone Table 6. V.44/V.42/V.42 bis MNP Command Summary connect state, transmits Table 7. Fax Identity Command Summary Table 8. Fax Class 1 Command SummaryTable 9. IS-101Voice Command Summary Table 10. Voice DTE→DCE Character PairsTable 10. Voice DTE→DCE Character Pairs Continued Table 11. Voice DTE←DCE Character PairsTable 12. Dial Modifiers Table 11. Voice DTE←DCE Character Pairs ContinuedTable 13. S-RegisterSummary Table 13. S-RegisterSummary Continued Data Mode AT COMMANDS Data Mode AT COMMANDSATW0 Table 14. Data Reporting Wn MappingFigure 3. Example of a Remote Connection •ATW2Intel Confidential +FMFR?, +FMDL?, +FREV? 3.7Hanging Up Hn, S10, Zn, &D2 3.6Online Command Mode Escape Codes, On3.8Modem-to-ModemConnection Data Rates Intel Confidential +VCID=1 +PMH=0+PCW=0 +++ATIntel Confidential hook to connect the call. Now you can answer the phone and talk. After completing your voice conversation, the modem will issue another +PMHF and ATO command to initiate a Quick Connect. If the server rejects the request to go on hold, the user can stay on line ATO command issued or disconnect from his initial data connection ATH command issued Table 16. Supported Modulation Types 3.9Diagnostic Testing S18, &Tn 3.9.1Local Analog Loopback AT&T1Figure 6. Local Analog Loopback Test 3.9.2Local Analog Loopback With Self-TestAT&T8LOCAL MODEM Local Modem or Test Modem3.10.1Time-IndependentEscape Sequence Licensing Requirements for Hayes Escape SequenceFormat <char1><char2><char3><AT command><contents of S3>char1 = char2 = char3 = escape character S2 Table 18. Data Mode Command Descriptions 3.10.2Hayes* Escape SequenceIntel Confidential Sn=x Intel Confidential Data Mode AT COMMANDS536EX Chipset Developer’s Manual Intel Confidential AT&V0 Intel Confidential Indication Command DefaultDefinition 1, 0, Intel Confidential +ETBM +ESR1, 1, +IFC +GMR+GSN +ILRR=mmodulations +MS=m <carrier>Description see ‘m’<value> +PHSW=+PMHF +PMHRIntel Confidential Error Correction and Data Compression Error Correction and Data Compression4Table 19. Operating Modes Table 20. Resulting +ES Connection Types NOTESIntel Confidential Error Correction and Data Compression536EX Chipset Developer’s Manual Intel Confidential +DS=m +DR=mdirection <max string>3768 +EFCS=m+ER=m +ES=m 5.2Fax Class 1 Commands Fax Class 1 AT Commands5.1Fax Identity Commands Fax Class 1 AT CommandsTable 23. <mod> Selection Table Figure 8. T.30 HDLC Frame Format Table 24. Fax Mode Command Descriptions Refer to Table 23 on page Table 24. Fax Mode Command Descriptions Continued+FRH=m shown in Table 23 on page+FTH=m IS-101Voice Mode AT Commands IS-101Voice Mode AT Commands6.1DTMF Detection Reporting Table 25. Voice Mode Command Descriptions6.2Relay Control +FLO=m m = <deassert>, <assert>m=<enable>, <report> +VDR=mm = <mask> +VEM=mIntel Confidential +VIP Preassigned Voice I/O Labels +VLS=mVoice I/O Primitive Codes Relay/Playback Control: contm = <sds>, <sdi> +VRX+VSD=m +VSM=m m= <cml>, <vsr>, <scs>, <sel>Transmission: Range: Compression Method Selection: cont +VSP=mfactory default is ‘0’ +VTS=m noneDescription CommandDefault DTMF and Tone Generation: contTable 26. S-RegisterCommand Descriptions S-RegistersS-Registers S-Registers Intel Confidential536EX Chipset Developer’s Manual S-Registers Intel Confidential536EX Chipset Developer’s Manual S-Registers Intel Confidential536EX Chipset Developer’s Manual S-Registers Caller ID Caller IDTable 27. Caller ID Tags for Formatted Reporting <DLE> R RING DATE = TIME = NMBR = NAME = DOE JOHN MESG =RING RING NMBR =Parallel Host Interface 16C450/16C550A UART Parallel Host Interface 16C450/16C550AUART Figure 11. UART Emulation in Intelsdb.VxDUART Transmitter Flow Diagram UART Receiver Flow DiagramADDRESS REGISTERBIT NUMBER NAMEFigure 14. Scratch Register SCR 9.2.1Scratch Register SCR9.2.2Modem Status Register MSR Figure 15. Modem Status Register MSR9.2.3Line Status Register LSR Figure 16. Line Status Register LSRFigure 17. Modem Control Register MCR 9.2.4Modem Control Register MCR9.2.5Line Control Register LCR Figure 18. Line Control Register LCRRegister 9.2.6FIFO Control Register FCRFigure 19. FIFO Control Register FCR Figure 20. Interrupt Identity Register IIR 9.2.7Interrupt Identity Register IIRTable 28. Interrupt Control Functions 9.2.9Transmitter Holding Register THR 9.2.8Interrupt Enable Register IERFigure 21. Interrupt Enable Register IER Figure 22. Transmitter Holding Register THRFigure 23. Receiver Buffer Register RBR 9.2.10Receiver Buffer Register RBR9.2.11Divisor Latch Registers DLM and DLL Figure 24. Divisor Latch Registers DLM and DLL9.3.1FIFO Interrupt Mode Operation 9.316C550A UART FIFO Operation9.3.2FIFO Polled Mode Operation Parallel Host Interface 16C450/16C550A UART Intel Confidential536EX Chipset Developer’s Manual
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