Intel 536EX User Manual

536EX Chipset

Developer’s Manual

January 2002

Order Number: 273584-002

Information in this document is provided in connection with Intel® products. No license, express or implied, by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Intel’s Terms and Conditions of Sale for such products, Intel assumes no liability
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intended for use in medical, life saving, or life sustaining applications.

Intel may make changes to specifications and product descriptions at any time, without notice.

Designers must not rely on the absence or characteristics of any features or instructions marked “reserved” or “undefined.” Intel reserves these for
future definition and shall have no responsibilit y wha tsoeve r for conflicts or incompat ibilities arisi ng from futu re changes to them.

The 536EX may contain design defects or errors known as errata which may cause the produc t to deviate from publishe d specificat ions. Current
characterized errata are available on request.

Contact your local Intel sales office or your distributor to obtain the latest specifications and befo re placi ng your product order.
Copies of documents which have an ordering number and are referenc ed in this docume nt, or other In tel literature may be obtained by callin g

1-800-548-4725 or by visiting Intel's website at http://ww w.intel.com.
Copyright © Intel Corporation, 2002
*Third-party brands and names are the property of their respective owne rs.

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Contents

Contents

1 Introduction......................................................................................................................................7

1.1 Controllerless Modem Driver Overview................................................................................7

1.1.1 Windows* M ill ennium Edition (Windows Me), Windows 2000, Windows XP, and
Windows NT* 47

1.1.2 Windows 95 and Windows 98..................................................................................8

1.2 V.90/V.92 and V.34 Data Modes... ................ .............................. ................. ........................9

1.3 Modem Connection Overvie w..................... ........................................... .............................10

1.4 AT Commands Overview....................................................................................................11

1.4.1 Se n din g Co mmands.. ... .............................. .............................. ................. ............12

1.4.2 AT Esca p e Sequen ce s..... .............................. ................ .............................. .........13

1.4.3 D i al Modifi e r.................. .... .............................. ................ .............................. .........13

2 AT Command Summary Tables....................................................................................................14

3 Data Mode AT COMMANDS.........................................................................................................26

3.1 Using AT Commands to Access the S-Registers [Sn?, Sn=x, ?]........................................26

3.2 Modem Responses and Comman d Echo [En , Vn, Xn, Wn, Qn]......... ... .............................26

3.3 Modem Reset and NVRAM Commands [DS=m, Zn, &F, &Vn, &Yn, &Wn, &Zn=x]...........28

3.4 Modem Identificatio n Commands [In, +F MI, +FMR, +F MM, +GMI, +GMM, +GMR, +GSN,

+FMFR?, +FMDL?, +FREV?].............................................................................................29

3.5 Establishing a Modem Connection [A, D, DS = n, S0]........................................................29

3.6 Online Command Mode [Escape Codes , On]........................ ................ .............................30

3.7 Hanging Up [Hn, S10, Zn, &D2]..........................................................................................30

3.8 Modem-to-Modem Connec ti o n Data Rates.............................. .............................. ............30

3.9 Diagnostic Testing [S18, &Tn]............................................................................................36

3.9.1 L oc al An alo g Loopb ac k [AT&T 1]... ... ................. .............................. ......................36

3.9.2 Local Analog Loopback With Self-Test [AT&T8]....................................................37

3.10 AT Escape Sequences .......................................................................................................38

3.10.1 Time-Independen t Esc ape Sequ en ce .......................................... ................ .........38

3.10.2 Hayes* Escape Sequence.............................. .............................. .........................40

4 Error Correctio n and Data Compre ssio n.. ........................................... .............................. ............56

5 Fax Class 1 AT Commands...........................................................................................................64

5.1 Fax Identity Commands......................................................................................................64

5.2 Fax Class 1 Commands .....................................................................................................64

6 IS-101 Voice Mode AT Commands...............................................................................................70

6.1 DTMF Detection Reporting.................................................................................................71

6.2 Relay Control......................................................................................................................71

7 S-Registers....................................................................................................................................85

8 Caller ID.........................................................................................................................................90

9 Parallel Host Interfa ce 16C45 0 /1 6C55 0A UART................ .... ........................................... ............92

9.1 UART Emulation in the Controllerless Modem...................................................................92

9.2 UART Register Definitions.................................................................................................. 95

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Contents

9.2.1 Scratch Register (SCR).........................................................................................95

9.2.2 Modem Status Register (MSR)..............................................................................95

9.2.3 Line Status Register (LSR).................................................................................... 9 6

9.2.4 Modem Control Register (MCR)............................................................................9 7

9.2.5 Line Control Register (LCR)..................................................................................97

9.2.6 FIFO Control Register (FCR)................................................................................. 9 8

9.2.7 Interrupt Identity Register (IIR)....................................... .............................. .........99

9.2.8 Interrupt Enable Register (IER) ...........................................................................100

9.2.9 Transmitter Holding Register (THR)....................................................................100

9.2.10 Receiver Buffer Register (RBR)...........................................................................101

9.2.11 Divisor Latch Registers (DLM and DLL)..............................................................101

9.3 16C550A UART FIFO Operation ......................................................................................102

9.3.1 FIFO Interrupt Mode Operati o n........ ... ................. .............................. .................102

9.3.2 FIFO Polled Mode Operation...............................................................................102

Figures

1 WDM Driver Block Diagram........ .............................. .............................. ......................................8

2 VxD Mini Port Driver Block Diagram.............................................................................................9

3 Example of a Remote Connection..............................................................................................27

4 Modem-on-Hold: Incoming Voice Call in Data Mode..................................................................32

5 Modem-on-Hold: Initiating a Voice Call in Data Mode................................................................33

6 Local Analog Loopback Test......................................................................................................3 7

7 Local Analog Loopback with Self-Test .......................................................................................3 7

8 T.30 HDLC Frame Format..........................................................................................................66

9 CLASS 1 DTE-Generated HDLC Frame Information (AT+FTH=<mod>)...................................6 6

10 CLASS 1 DTE Reception of HDLC Frame Information (AT+FRH=<mod>) ...............................66

11 UART Emulation in Intelsdb.VxD................................................................................................92

12 FIFO Buffers for Transmitter and Receiver ................................................................................93

13 Parallel Host Interface UART Register Bit Assignments............................................................94

14 Scratch Register (SCR)..............................................................................................................95

15 Modem Status Register (MSR)...................................................................................................95

16 Line Status Register (LSR).........................................................................................................9 6

17 Modem Control Register (MCR).................................................................................................97

18 Line Control Register (LCR).......................................................................................................9 7

19 FIFO Control Register (FCR)...................................................................................................... 9 8

20 Interrupt Identity Register (IIR)...................................................................................................9 9

21 Interrupt Enable Register (IER) ................................................................................................100

22 Transmitter Holding Register (THR).........................................................................................100

23 Receiver Buffer Register (RBR) ............................................................................................... 101

24 Divisor Latch Registers (DLM and DLL)...................................................................................101

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Contents

Tables

1 DTE-to-DCE Data Rates for Each Mode....................................................................................11

2 DCE-to-DCE Data Rates for Each Mode....................................................................................11

3 DCE-to-ISP Data Rates for V.90 Mode......................................................................................11

4 DTE-Modem Data Rate Response Codes... .............................. ............................................ .....12

5 Data Mode Command Summary................. .............................. ................. .............................. ..14

6 V.44/V.42/V.42 bis MNP Command Summary...........................................................................19

7 Fax Identity Command Summary...............................................................................................21

8 Fax Class 1 Command Summary...............................................................................................21

9 IS-101 Voice Command Summary.............................................................................................22

10 Voice DTEÆDCE Character Pairs..................... .............................. .............................. ............22

11 Voice DTE¨DCE Character Pair s........... ................ .............................. .............................. .........23

12 Dial Modifiers......................................... .............................. ................ .......................................24

13 S-Register Summary ..................................................................................................................24

14 Data Reporting Wn Mapping ......................................................................................................27

15 Product Identifica tion Inf ormat i on.................... ................ ................. .............................. ............29

16 Supported Modulation Types......................................................................................................35

17 Resulting Modem-to-Modem Connection Rates with Non-Default Values .................................36

18 Data Mode Command Description s............. ................. .............................. .............................. ..40

19 Operating Modes........................................................................................................................56

20 Resulting +ES Connection Types...............................................................................................57

21 V.44/V.42/V.42 bis and MNP Data Modem Command Descriptions ..........................................57

22 Fax Identity Command Descriptions...........................................................................................64

23 <mod> Selection Table ...............................................................................................................65

24 Fax Mode Command Descriptions ............................................................................................. 67

25 Voice Mode Command Descriptions ..........................................................................................71

26 S-Register Command Descriptions............................................................................................85

27 Caller ID Tags for Formatted Reporting......................................................................................90

28 Interrupt Control Functions.........................................................................................................99

29 Programmable Data Rates.......................................................................................................101

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Contents

Revision History

Date Revision Description

January 2002 002

August 2001 001 Initial release

Changed references to “HaM Data Fax Voice” to “Intel 536EP
V.92 Modem.”

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Introduction 1

This developer’s manual describes the software interface for Intel® 536EX (controllerless and
controll e r) chipset solu tions. The controllerless-b a sed solutions include the 536EP for PCI and
Mini-PCI. Re fer to the chipse t da tasheets for the detailed chipset descriptions (public order
numbers 273503-001, 273xxx-001, 273 xxx-001, 273xxx-001, and 273xxx-001).

The controllerless-bas ed chi ps et, as the name implies, does not have a dedicated hardware
controller . The control ler functi ons are execu ted by th e CPU. This deve loper’ s man ual inclu des the
AT command sets for da ta, fax, and voice and the UAR T interface and emulation. Like the earlier
solutions from Intel, the 536E X chipsets support a variety of applications without the need of
additional firmware de velopment. Note, the supported AT commands are firmware or driver
version dependent.

1.1 Controllerless Modem Driver Overview

1.1.1 Windows* Millennium Edition (Windows Me), Windows 2000, Windows XP, and Windows NT* 4

The controllerless modem chipsets are integrated into the Microsoft* Windows* Me, Windows
2000, Windows XP, and Windows NT* 4 operating systems via proprieta ry Intel® Windows
Driver Model (WDM) modem drivers. These driver s are fully plug and play capable and conform
to all Microsoft WHQL certification requirements.

The funct i on a l blo c k di a g ra m in Figure 1 shows the common WDM architecture for the
Microsof t’s operating systems supporting c ommon WDM drivers model.

User-mode applic ation, via special W indows API (FILE, T API, UNIMODEM), can access a virtual
COM port prov ided by the Intel WDM driver. T he da ta flow is conver te d inside the driver in
accordance with some compressio n and a channel level protocol and passed to the DSP. The
control flow fo llows the common Micros oft WDM driver model. The Intel WDM driver is
installed as a stack of filter dri ver s be low the system modem.sys driver.

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Introduction

Figure 1. WDM Driver Block Dia g ram

applications

User applications

virtual COM

protocols

User

Kernel - ring0

Modem drivers stack

port,

channel

layer

WDM driver
Intels51.sys

PCI bus

Hardware

1.1.2 Windows 95 and Windows 98

When the controllerless modem chipsets are used with Microso ft Windows 95 and Windows 98
applications, the traditional UART and serial port emulations are replaced by the propri etary HaM
Mini Port driver (see Figure 2). Instead of transferring commands to UART vir tual registers, then
to a serial port, the HaM Port Driver sends commands directly to the Windows virtual machine
driver VCOMM. VxD. This low-level communication driver supports the Win16 and Win32
Communication APIs. Like the WDM drivers, the Mini Port VxD drivers are fully plug and play
and conform to Microsoft WHQL certification requirements.

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When the controllerle ss chipsets are used with MS-DOS* applications, however, a UART
emulation is required. Intel provides an additional driver called Intelsdb.VxD, which includes a
UAR T em ulation. Please refer to Section 9.1, “UAR T Em ulation in the Controllerless Modem” on

page 92 for an explanation of the 536EX UART emulation. The Intelsdb.VxD driver interacts

directly with the VCOMM.VxD dr iver using the Win16 and Win32 Communi c a tion APIs.

Figure 2. V xD Mini Port Driver B lock Dia gram

NON-SYSTEM
VIRTUAL MACHINE
MS-DOS SHELL APPLICATION
OR DRIVER

Introduction

SYSTEM VIRTUAL MACHINE

MS-DOS
APPLICATION

Intelsdb.VXD

WINDOWS
APPLICATION

TAPI

Unimodem COMM.DRV

VCOMM.VXD

HaM Port Driver

Interrupt Services

Chipset Hardware



Win 16

1.2 V.90/V.92 and V.34 Data Modes

The 536EX chipset defaults to the V.90 or V.92 mode depending on the driver version. The V.90/
V.92 mode allows receive data rates of up to 56,000 kbps over the PSTN (public switched
telephon e network) only in connections with equipment-compatible ISPs (Internet Service
Providers); howev e r, FCC regulations limit receive speeds to 53,333 kbps due to excessive power
demands at higher speeds. In modem-to-modem connections, V.90/V.92 mode falls back to V.34
mode in both the transmit and receive directions. The chipsets implement all data rates and
modulation schemes for ITU-T (International Telecommunications Union-Telecommunications)
standards V.34, V.32 bis, V.32, V.22 bis, V.22, V.21, Bell 212A, and Bell 103.

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Introduction

1.3 Modem Connection Overview

The DCE (modem) operates in one of two states: command or online. In each state, both data and
commands (i nc luding DCE res ponses) are transferred through the UART THR (Transmit Holdi ng
register) and the RBR (Receiver Buffer register).

The modem defaults to the command state. I n the command stat e, the DTE (host) communica tes to
the modem through AT commands and S-registers. AT commands are character strings that help
guide modem operation. S-r e gisters are internal modem registers that the DT E can access. The S­registers contain mode m st a t us 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 ar e fi rmwar e r evis io n-dep ende nt ( that is , not a ll comma nds are suppo rt ed
by all modem models or all firm ware 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 com man d line from the DTE. A <CR> informs the
modem that the entire command string has been trans mitted and that the modem sho uld start
processing all the commands wit hin the command line.

A command line may include one or more AT commands that may or may not be separate d by a
space. AT commands may be either upper- or lower-case characters, but all characters for a given
command must use the same cas e. If t here ar e mult iple co mmands in a li ne, a sem icolo n (;) must b e
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 mo dem (while in command state only). The last comm and
may be repeated by typing A/ witho ut 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 infor mat ion to the DTE in the form of response code s. These response
codes can be expressed in text or numeric form. The support e d response codes are provided in

T a ble 4 on page 12.

Examples of mo de m 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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The mode m rec ogn ize s AT comman ds f r om th e D TE at any val id data ra te f rom 30 0 bps t o 115,200
bps (that is, the modem autobau ds up to 115,200 bps); however, the DTE should use the data r a te
specified for each mode according to the transmitting dir ection—DTE-to-modem (Table 1) or
modem-to-modem (Table 2). The V.90 and V .92 data rates are effective only in DCE-to- IS P
connections.

T able 1. DTE-to-DCE Data Rates for Each Mode

Mode Data Rate (bps) Affected Data

Data (V.34) 2400–115,200

Data (V.92) 28,800–115,200
Fax 19,200

Voice 19,200–115,200

Table 2. DCE-to-DCE Da ta Rates for Each M o d e

Mode Data Rate (bps) Affected Data

Introduction

DTE-to-modem data rate Data (V.90) 28,800–115,200

AT commands, playback and record modes
(varies according to compression type)

Data (V.34)
(transmit and receive)

Fax 300–14,400
Voice 19,200–115,200

2400–33,600

T able 3. DCE-to-ISP Data Rates for V.90 Mode

Mode Data Rate (bps) Affected Data

Data (V.90) transmit 4800–33,600
Data (V.90) receive 28,000–56,000
Data (V.92) transmit 24,000–48,000
Data (V.92) receive 28,000–56,000

Each comma nd ma y ha ve on e or mo re p aram et ers ass oci ated w ith it. If a pa ram eter is not se nt f or a
command requiring a numeric parameter, then the mod em ass ume s a zero (‘0’) parameter (only if
zero is a valid parameter for the command ). Fo r example, ATZ and ATZ0 commands perform
identical functi ons (that is, the modem sees ‘ATZ’ and automatically uses the ‘0’ param e ter during
processi ng the command). Other commands do not us e pa rameters.

1.4 AT Commands Overview

DTE-to-modem data rate

AT commands, playback and record modes
(varies according to compression type)

ISP-to-modem data rate

The AT command set and S-registers are divided into fo ur categori es: data , Group 3 fax, voice, and
V.42/MNP. Summaries of all commands are provided later on in this ch apter.

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Introduction

1.4.1 Sending Commands

All command lines sent to the modem, except for A/, must be preceded by an ‘AT’ and terminated
by the contents of S-register S3 (typically a carriage return <CR>). AT stands for ‘attention’ and
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 to begin processing all the commands in the
command line. A command line can include one or more AT commands. The commands can be
separated by a space, if desired, but no punctuation is needed except for extended commands.
Extended commands begin with a ‘+’, such as fa x, voice, and V.250 commands. In a multiple­command line, extended AT commands must be separated from following commands by a
semicolon(;).

Examples:

ATS1?<CR>
A/
AT &F &D2 +FCLASS=?<CR>
AT +FCLASS=0; S0=1<CR>

The modem provides status information to the DTE in the form of response codes, as listed in

Table 4. Response codes take two (2) forms, text (ATV1) or numeric (ATV0), depending on how

the modem is confi gured.

Table 4 lists basic for mat response codes. These response codes have numeric equivalents that are

displayed depending on the value of ATV. In addition to th e ba sic format response codes, there are
extended syntax result codes that in dicate connection status of the DCE-DCE connection that are
not effected by numeric response rep orting. These result codes have no numeric equivalent and are
always issued in text form. The res ult codes displ a y modem mode, transmit connection rate, error
correction, compression, DTE rate, and receive rate. Note that the final connection message only
indicates receive ra te i f ATXn is greater t han 0. The format for the re sult codes code de pends on the
Wn command. The setting of the Wn command will determine which of the following connect
results codes are disp layed ( +MCR, + MRR, +E R, + DR, +I LRR). Refe r to the Wn comm and for the
detailed description of the command. Note that the supported carrier mo des for +MCR can be
found in p arameter 1 of +MS. The last result code is the CONNECT <text>, where tex t is the DCE
receive rate. Note, the CONNECT <text> is not displayed when ATX0 is indicated, just
CONNECT is displayed and is reported by the rules in Table 4.

Table 4. DTE-Modem Da ta Rate Res po n s e Co d es

Numeric Text Numeric Text

0 OK 9 DELAYED CALL
1 CONNECT 10 BLACKLISTED
2RING11+FCERROR
3 NO CARRIER 12 RINGBACK
4ERROR13CPON=
6 NO DIALTONE 14 CPOF=
7 BUSY 15 DRON=
8 NO ANSWE R 16 DROF=

After sending an AT command string to the modem, the DTE must wait for a response code from
the modem befor e sending a new AT command strin g to the modem.

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1.4.2 AT Escape Sequences

The 536EX provides the industry-standard escape sequence, TIES (Time Independent Escape
Sequence). TIE S is designed to work with existing communication software writt en for the Hayes
Escape Sequence.

Upon special request, Ambient provides the Hayes* Escape Sequence; however, please note that
licensing can be required.

TIES/Hayes * Escape Sequenc e s
The 536EX modem c hipset is manufa c tured with TIES (Time Independent Escape Sequence) as

the default setti ng. It is Hayes’ position that you must have a valid license fr om Hayes Micro
Computer of Norcross, Georgia, before producing modem systems that us e the Hayes Escape
Sequence.

Intel accepts no responsibility and does not indemnify nor in any way pro vide protection for
patent or possible patent violations to its customers or users of it products.

1.4.3 Dial Modifier

Introduction

Command Function

0 to 9 Dialing digits
A, B, C, D, *, # Tone dial characters
P Pulse dial
R Reverse Originate mode
S=n Dial NVRAM telephone number
T Tone dial
W Wait for dial tone
, Pause
! Flash hook
@ Wait for quiet answer
; Return to command state

- ( ) Ignored by modem

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AT Command Summary Tables

AT Command Summary Tables 2

This section contains summary tables of all AT commands, S-regis ters, and bet ween AT commands
and S-regis t e rs. These commands are fully described in the rel e va nt sections of the 536EX
Developer’s Manual.

Table 5. Dat a Mode Comma nd Su mma ry

Note Command Function Default Range

** A/ Repeat last command none – no

A Answer none – no
Cn Carrier control option 1 0, 1 no

C0 Transmit carrier always off
C1 Normal transmit carrier

D Dial command none – no

* En Command mode echo 1 0, 1 yes

E0 Disables echo
E1 Enables echo

Hn Switch hook control 0 0, 1 no

H0 Hangs up the telephone line
H1 Picks up the telephone line

In Identification/checksum option 0

I0 ROM Checksum
I1 Modem Name
I2 Manufacturer
I3 Chipset
I4 Firmware Version
I5 Modem Chip Hardware Configuration
I6 DSP Patch Level
I12 Country Code
I7–I11, I13,

I14, I20–
I25

* Ln Speaker volume control 2 0–3yes

L0 Low speaker volume
L1 Low speaker volume

L2 Medium speaker volume
* Value saved in NVRAM.
** Command not preceded by an ‘AT.’

Reserved

0–7, 10–11,
14, 20–23

Reported

by &Vn

no

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Table 5. Data Mode Command Summary (Continued)

AT Command Summary Tables

Note Command Function Default Range

L3 High speaker volume

* Mn Speaker control 1 0–3yes

M0 Speaker always off
M1 Speaker on until carrier present
M2 Speaker always on

M3

On Go online 0 0, 1, 3 no

O0 Returns modem to Data mode
O1

O3

* P Select pulse dialing none – yes
* Qn Result code display control 0 0, 1 yes

Q0 Enables result codes
Q1 Disables result codes

Sn Select an S-register none 0–33 no
Sn=x Write to an S-register none

Sn? Read from an S-register none 0–33 no
* T Select tone dialing none – no
* Vn Result code form 1 0, 1 yes

V0 Choose numeric form
V1 Choose verbose (text) form

* Wn Response code data rate 0 0–4yes

W0, W1 DTE data rate
W2 Modulation, DCE TX rate

W3

W4

* Value saved in NVRAM.
** Command not preceded by an ‘AT.’

Speaker off during dialing; speaker on until
carrier present

Retrains equalizer and then returns to Data
mode

Renegotiates rate and then returns to Data
mode

n = 0–33
x = 0–255

Modulation, DCE TX rate, Error Correction,
Compression and DTE data rate

Modulation, DCE TX rate, Error Correction,
Compression

Reported

by &Vn

no

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AT Command Summary Tables

Table 5. Data Mode Command Summary (Continued)

Note Command Function Default Range

* Xn Result code type 4 0–4yes

X0

X1

X2

X3

X4

* Yn Long space disconnect 0 0, 1 yes

Y0 Disables long space disconnect
Y1 Enables long space disconnect

Zn Recall stored profile 0 0, 1 no

Z0 Resets modem and recalls user profile 0
Z1 Resets modem and recalls user profile 1

* &Cn DCD (data carrier detect) option 1 0, 1 yes

&C0
&C1 DCD set according to remote modem status

&Dn DTR (data terminal ready) option 2 0–3yes

&D0 In Async mode, modem ignores DTR

&D1

&D2

&D3

&F Load factory defaults none – no

*&Gn

&G0 Disables guard tone
&G1 Enables 550 Hz guard tone
&G2 Enables 1800 Hz guard tone

&Kn Select serial flow control 3 0, 3, 4 yes
* Value saved in NVRAM.
** Command not preceded by an ‘AT.’

Enables result c odes 0–4; disables detection
of busy and dial tone

Enables result codes 0–5, 10, and above;
disables busy and dial tone detection

Enables result codes 0–6 and 10 and above;
disables busy detection and enables dial
tone detection

Enables result codes 0–5, 7, and 10 and
above; enables busy detection and disables
dial tone detection

Enables result codes 0–7 and 10 and above;
enables busy and dial tone detection

Ignores remote modem status; DCD always
on

Modem switches from data mode to
command mode when an on-to-off transiti on
of DTR occurs

When DTR switches off, the modem goes
on-hook and disables Auto-answer mode;
when DTR switches on, auto-answer is
enabled

Turning off DTR re- initializ es the modem and
resets values except UART registers

Guard tone option (1200 bps and 2400 bps
only)

00–2yes

Reported

by &Vn

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Table 5. Data Mode Command Summary (Continued)

AT Command Summary Tables

Note Command Function Default Range

&K0 Disables flow control
&K3 Bidirectional hardware flow control
&K4 XON/XOFF software flow control

* &Pn Dial pulse ratio 0 0, 1 yes

&P0

&P1

* &Sn DSR (data set ready) option 0 0, 1 yes

&S0 DSR is always active
&S1

&Tn Self test commands 0 0–1, 8 no

&T0 Terminates test in progress
&T1 Initiates local analog loopback

* &Un Disable Trellis coding 0 0, 1 no

&U0 Enables Trellis coding with QAM as fallback
&U1 QAM modulation only

&Vn View active and stored profiles 0 0, 1, 3 no

&V0 View active profile and stored profile 0
&V1 View active profile and stored profile 1

&Wn Stored active profile 0 0, 1 no

&W0 Store in user profile 0
&W1 Store in user profile 1

* &Yn Select stored profile on power up 0 0, 1 yes

&Y0 Recall stored profile 0 on power-up
&Y1 Recall stored profile 1 on power-up

&Zn=x

* %En Auto-retrain control 1 0, 1 yes

%E0 Disables auto-retrain
%E1 Enables auto-retrain

* %Gn Rate renegotiation 1 0, 1 yes

%G0 Disabled

%G1 Enabled
* Value saved in NVRAM.
** Command not preceded by an ‘AT.’

Sets 10 pps pulse dial with 39%/61% make­break

Sets 10 pps pulse dial with 33%/67% make­break

DSR active only during handshaking and
when carrier is lost

Store telephone number (up to 30 digits) to
location ‘n’ (0–3)

none

n = 0–3
x = 0–9 A B
C D # * T P
R W @ , ! ;

Reported

by &Vn

no

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AT Command Summary Tables

Table 5. Data Mode Command Summary (Continued)

a

Reported

by &Vn

no

no

Note Command Function Default Range

* -Cn Generate data mode calling tone 0 0–2no

-C0 Calling tone disabled

-C1 1300 Hz calling tone enabled

-C2 V.8 calling tone and 1300 Hz calling tone
+A8E=m V.8 and V.8 bis operation controls
+EB Controls break handling 1, 0, 30 See note no

+ESA Synchronous access mode configuration
+ESR Controls selective repeat option in V.42 1 0–2no

+ETBM Controls call termination buffer management 1, 1, 20 See note no
+GCAP Request complete capabilities list none no
+GCI Country of installation none no
+GMI Identify modem manufacturer none – no
+GMM Identify product model none – no
+GMR Identify firmware version none – no
+GSN Identify product serial number ID none – no
+IFC Controls DTE-DCE flow control 2, 2 See note no
+ILRR=m Controls local rate reporting 0 0, 1 no

m=0 Disabled

m=1 Enabled
+MA Controls modulation automode – See note no
+MR=m Selects modulation 0 See note no

m=0 Disabled

m=1 Enabled
+MS=m Modulation selections
+PCW=m Call waiting enable 0 no

+PHSW=m Controls 2C relay none 0, 1 no
+PIG=m PCM upstream ignore 1 no
+PMH=m Modem on hold enable 0 no
+PMHF V.92 modem on hold hook flash none no
+PMHR Initiate modem on hold none no
+PMHT=m Modem on hold timer 0 no
+PQC=m V.92 phase 1 and phase 2 control 0 no
+PSS=m Use short sequence 2 no

* Value saved in NVRAM.
** Command not preceded by an ‘AT.’

1, 1, C1,
0, 0

0, 0, 1, ,
0, 0, 0,

V92, 1,
0, 0, 0, 0

See note no

See note

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AT Command Summary Tables

a. For Data mode, the factory default setting is AT+MS=V92, 1, 0, 0, 0, 0 to send at speeds of 33,600 bps or

below and receive at speeds of 53,333 bps and below.

Note: See the relevant sections in the 536EX Developer’s Manual for full command description and

parameter ranges.

T able 6. V.44/V.42/V.42 bis MNP Command Summary

Note Command Function Default Range

* %An Set auto-reliable fallback character 13 0–127 yes
* %Cn MNP 5 data compression control 1 0, 1 yes

%C0 No compression
%C1 Enables MNP5 data compression

* \An MNP block size 3 0–3yes

\A0 Maximum 64 characters
\A1 Maximum 128 characters
\A2 Maximum 192 characters
\A3 Maximum 256 characters

\Bn Set transmit break 3 0–9

* \Cn Set auto-reliable buffer 0 0–2yes

\C0 No data buffering

Four-second buffer until 200 charact ers in the buffer or

\C1

detection of a SYN character
No buffering. Connects non-V.42 modems to V.42

\C2

modem

* \Gn Set modem port flow control 0 0, 1 yes

\G0 Disables port flow control
\G1 Sets port flow control to XON/XOFF

* \Jn bps rate adjust control 0 0, 1 yes

\J0 Disables rate adjust
\J1 Enables rate adjust

\Kn Set break control 5 0–5no

connect state, transmits

\K0

command state, transmits
connect state, receives
connect state, transmits

\K1

connect state, receives

* Value saved in NVRAM.

Enters command mode,
no break sent

Destructive/expedited

Destructive/expeditedcommand state, transmits

Reported

by &Vn

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AT Command Summary Tables

Table 6. V.44/V.42/V.42 bis MNP Command Summary (Continued)

Note Command Function Default Range

connect state, transmits

\K2

command state, transmits
connect state, receives
connect state, transmits

\K3

connect state, receives

connect state, transmits

\K4

command state, transmits
connect state, receives
connect state, transmits

\K5

command state, transmits

connect state, receives
* \T0 Disables inactivity timer 0 0–90 yes
* \Xn Set XON/XOFF pass-through 0 0, 1 yes

\X0 Processes flow control characters

\X1

* -Jn Set V.42 detect phase 1 0, 1 yes

-J0 Disables the V.42 detect phase

-J1 Enables the V.42 detect phase

* “Hn V.42 bis compression control 3 0–3yes

“H0 Disables V.42 bis
“H1 Enables V.42 bis only when transmitting data
“H2 Enables V.42 bis only when receiving data

“H3

“On V.42 bis string length 32 6–250 no
+DR=m Controls data compression reporting 0 0, 1 no

* +DS=m Controls V.42 bis data compression
* Value saved in NVRAM.

Processes flow control characters and passes to local

or remote

Enables V.42 bis for both transmitting and receiving

data

m=0 Disabled
m=1 Enabled

Enters command mode,
no break sent

Nondestructive/expedited

Nondestructive/expeditedcommand state, transmits

Enters command mode,
no break sent

Nondestructive/
nonexpedited

Nondestructive/
nonexpedited

3, 0,
2048, 6

See note yes

Reported

by &Vn

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AT Command Summary Tables

Table 6. V .44/V.42/V .42 bis MNP Command Summary (Continued)

Note Command Function Default Range

+DS44=m V.44 Data Compression

+EFCS
+ER=m Controls error control reporting 0 0, 1 no

* +ES=m Error control selection 3, 0, 2 See note yes
* Value saved in NVRAM.

Controls the 32-bit frame check sequence option in
V.42

m=0 Disabled
m=1 Enabled

Table 7. Fax Identity Command Summary

Command Function Default Range Reported by &Vn

+FMDL? Identifies product model none – no
+FMFR? Identifies modem manufacturer none – no
+FMI Identifies modem manufacturer none – no
+FMM Identifies product model none – no
+FMR Identifies product version number none – no
+FREV? Identifies product version number none – no

Reported

by &Vn

3, 0, 0,
471,
942,
140,
140,
1884,
3768

00–2no

no

Table 8. Fax Class 1 Command Summary

Command Function Default Range

+FCLASS=1 Mode selection 0 0, 1, 8 no
+FRH=m Receive HDLC data none 3 no

+FRM=m Receive data none

+FRS=m Wait for silence none 1–255 no
+FTH=m Transmit HDLC data none 3 no

+FTM=m Transmit data none
+FTS=m Stop transmission and pause none 0–255 no

24, 48, 72, 73, 74, 96, 97, 98, 121, 122,
145, 146

24, 48, 72, 73, 74, 96, 97, 98, 121, 122,
145, 146

536EX Chipset Developer’s Manual 21

Reported

by &Vn

no

no

Intel Confidential

AT Command Summary Tables

Table 9. IS-101 Voice Command Summary

Command Function Default Range Reported by &Vn

+FCLASS=8 Voice mode selection 0 0, 1, 8 no
+FLO=m Flow Control Select 1 0–2 no
+VBT=m Buffer threshold setting 192, 320 192, 320 no
+VCID=m Caller ID selection 0* 0 –2no

+VDR=m Distinctive Ring selection 0,0

+VEM=m Event reporting and masking

+VGM=m Speakerphone microphone gain 128 121–131 no
+VGR=m Receive gain selection 128 121–131 no
+VGS=m Speakerphone speaker gain 128 121–131 no
+VGT=m Volume selection 128 121–131 no
+VIP Initialize parameter ––no
+VIT=m DTE/DCE inactivity timer 0 0–255 no
+VLS=m Hardware type control 0 0–15 no
+VNH=m Automatic hang-up control 0 0–2no
+VRA=m Ringback-goes-away timer 50 0–50 no
+VRN=m Ringback-never-appeared timer 10 0–255 no
+VRX Record mode none – no
+VSD=m Silence detection (quiet and silence) 128, 50 See note no
+VSM=m Compression method selection 140, 8000, 0, 0 See note no
+VSP=m Speakerphone on/off control 0 0, 1 no
#VSPS=m Speakerphone type selection 1 0, 1 no
+VTD=m Beep tone duration timer 100 5–255 no
+VTS=m DTMF and tone generation none See note no
+VTX Play mode none – no
* The noted parameters, commands, and responses depend on the capability to receive.

‘C’
BB860980
BFE63883
BB863EE0

0–255,
0–255

– no

no

Note: See the complete command descr iption in the 536EX Developer’s Manual for rang e inf o rma t i on .

Table 10. Voi ce DTE→DCE Character Pairs

Response Hex Code Function

<NUL> 00 Do nothing
<DLE> 10 Two contiguous <DLE><DLE> codes indicate a single <DLE> in the data stream
<SUB> 1A <DLE><DLE> in data stream
<ETX> 03 End transmit data state
/ 2F Start of DTMF tone shielding

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Table 10 . Voice DTE →DCE Character Pairs (Continued)

Response Hex Code Function

<DEL> 7F DTMF transition to off
u 75 Bump up the volume
d 64 Bump down the volume
<ESC> 1B End receive data state
! 21 Receive data abort
<CAN> 18 Clear transmit buffer of voice data
? 3F Transmit buffer space available query

Table 11 . Voice DTE←DCE Character Pairs

Response Hex Code Function

<DLE> 10 Single <DLE> character in the data stream
<SUB> 1A <DLE><DLE> in data stream
<ETX> 3 End of Record mode data
X 58 Packet header for ‘Complex Event Detection Report’
. 2E Packet terminator for the ‘Complex Event Detection Report’
/ 2F Start of DTMF tone shielding
<DEL> 7F DTMF transition to off
0–930–39 DTMF tones 0–9
A–D41–44 DTMF tones A–D
* 2A DTMF tone *
# 23 DTMF tone #
o 6F Receive buffer overrun
c 63 1100 Hz fax calling tone
e 65 1300 Hz data calling tone
h 68 Local phone goes on hook
H 48 Local phone goes off hook
s 73 Presumed hang-up silence time-out
q 71 Presumed end-of-message quiet time-out
I 6C Loop current interruption
L 4C Loop current polarity reversal
r 72 Ringback
b 62 Busy/reorder/fast busy
d 64 Dial tone detected
u 75 Transmit buffer under-run
p 70 Line voltage increase (extension phone goes on-hook)
P 50 Line voltage decrease (extension phone goes off-hook)
a 61 Fax or data answer tone (2100 Hz)

AT Command Summary Tables

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AT Command Summary Tables

Table 11. Voice DTE←DCE Character Pairs (Continued)

Response Hex Code Function

f 66 Data answer detected (2225 Hz)
R 52 Incoming ring
% ‘ (,) 25, 26, 27, 28, 29 Manufacturer-specified

Table 12. Dial Modifiers

Command Function

0 to 9 Dialing digits
A, B, C, D, *, # Tone dial characters
P Pulse dial
R Reverse Originate mode
S=n Dial NVRAM telephone number
T Tone dial
W Wait for dial tone
, Pause
! Flash hook
@ Wait for quiet answer
; Return to command state

- ( ) Ignored by modem

Table 13. S-Regist er S u m mary

Note Register Functio n Default Range Units Reported by &Vn

* S0 No. of rings to auto-answer on 0 0–255 ring yes

S1 Ring count 0 0–255 ring yes

* S2 Escape character 43 0–127 ASCII yes

S3 Carriage return character 13 0–127 ASCII yes
S4 Line feed character 10 0–127 ASCII yes

S5 Backspace character 8 0–32, 127 ASCII yes
* S6 Wait before dialing 2 2–255 second yes
* S7 Wait for carrier 60 1–255 second yes
* S8 Pause time for dial modifier 2 0–255 second yes
* S9 Carrier recovery time 6 1–255 0.1 second yes
* S10 Lost carrier hang up delay 14 1–255 0.1 second yes
* S11 DTMF dialing speed 70 50–255 ms yes
* S12 Guard Time 50 0–255 (0.02 second) yes
* S14 Bit-mapped options 138 –– no
* Value saved in NVRAM.

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Table 13. S-Register Summary (Contin ued)

Note Register Function Default Range Units Reported by &Vn

S16 Modem test options 0 –– no
* S18 Modem test timer 0 0–255 second yes
* S21 Bit-mapped options 48 –– no
* S22 Bit-mapped options 118 –– no
* S25 Detect DTR change 5 0–255 0.01 second yes
* S30 Disconnect inactivity timer 0 0–255 minute yes
* S33 Sleep mode timer 10 0–90 second yes
* Value saved in NVRAM.

AT Command Summary Tables

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Data Mode AT COMMANDS

Data Mode AT COMMANDS 3

The 536EX chipsets implement:

• Standa rd Hayes*-comp a tible AT commands and S-regis ters in data mode

• Stand a rd EIA/TIA-578 AT commands in Class 1 fax mode

• Additional AT command sets for error correction, data compr es sion and voice mode

In data mode, the AT commands configure the DCE (modem) to establish a connecti on with a
remote data modem. In data mode, the 536EX chipsets execute the AT commands for error
correctio n (MNP 2-4, V.42) and data compression (MNP 5, V.42 bis) descr ibe d in Table 21 on

page 57, as well as the fax and voice mode commands AT+FCLASS=1 (fax) and AT+FCLASS=8

(voice).

3.1 Using AT Commands to Access the S-Registers [Sn?, Sn=x, ?]

The DTE can access the S-registers through the ATSn?, ATSn=x, and ? commands. For example,
to configure the modem to automatically answer a data modem call after two rings, type ATS0=2.

Examples:

ATS0=2 Configures S-register S0 to ‘2’
ATS0? Reads the contents of S-register S0
ATS0= Configures S-register S0 to ‘0’
AT? Reads the contents of the last accessed (read or write) S-register

3.2 Modem Responses and Command Echo [En, Vn, Xn, Wn, Qn]

The ATEn command configures the DCE to send back to the DTE any data that the DTE sent to
the DCE while in comm and mode. The ATVn command sets the DCE respons e codes to eit her tex t
or numeric form. For example, upon successfull y processing an AT command string, the DCE
sends an ‘OK’ (text) or a ‘0’ (numeric) to the DTE.

Examples:

Modem Setup

Echo, Numeric (E1, V0) AT<CR> AT<CR>0<CR>

Echo, Text (E1, V1) AT<CR> AT<CR><CR><LF> OK<CR><LF>

Host

Command

ATS0?<CR> ATS0?<CR>000<CR><LF>0<CR>

ATS0?<CR> ATS0?<CR><CR><LF>000<CR><LF><CR>

<LF>OK<CR><LF>

Modem Response

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Data Mode AT COMMANDS

Modem Setup

No Echo, Numeric (E0, V0) AT<CR> 0<CR>

No Echo, Text (E0, V1) AT<CR> <CR><LF>OK<CR><LF>

The DCE can be configures to use different response codes depending on th e V.250 command that
is enabled (AT+MR, AT+ER, AT+DR, and AT+ILRR). Alternatively, the ATWn command can
be used to set these V.250 commands. The mapping for the ATWn command to V.250 commands
is shown in Table 14. The setting for the ATXn command (page 43) can affect which ATWn
response codes are reported to the DCE. The ATXn command configures the modem c a ll progress
detection and reporting requirement s during dialing (for example, dial tone and busy tone
detection). The ATQn command selects whether the modem se nds result codes t o the DTE.

Table 14. Data Reporting Wn Mapping

Wn +ER +DR +MR +ILRR

W0 Disable Disable Disable Disable
W2 Disable D isable Enable Enable
W3 Enable Enable Enable Enable
W4 Enable Enable Enable Disable

Host

Command

ATS0?<CR> 000<CR><LF>0<CR>

ATS0?<CR> <CR><LF>000<CR><LF><CR><LF>OK

<CR><LF>

Modem Response

For example, a connection is established with the remote modem as shown below (with LAPM
error correction and V.42 bis da ta compression). The telephone line (or modem-to-modem
connection) data rate is 33,600 bps and the local UART (DTE-to-modem) connection rate is
115,200 bps.

Figure 3. Example of a Remote Connection

UART

DTE

Interfac e

(115,200 bps)

LOCAL MODEM

The modem then sends the ‘CONNECT’ messages for the following four Wn commands:

• ATW0

ILRR: 115200
CONNECT 50666

• ATW2

+MCR: V90
+MRR: 28800
CONNECT 50666

Telephone

Line

(33,600 bps)

REMOTE MOD EM

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Data Mode AT COMMANDS

• ATW3

+MCR: V90
+MRR: 28800
+ER: LAPM
+DR: V42B
+ILRR: 115200
CONNECT 50666

• ATW4

+MCR: V90
+MRR: 28800
+ER: LAPM
+DR: V42B
CONNECT 50666

3.3 Modem Reset and NVRAM Commands [DS=m, Zn, &F, &Vn, &Yn, &Wn, &Zn=x]

On powering-up, the DCE defaults to the configuration speci fied in NVRAM. The DCE may th en
be configured as needed. The DTE stores the DCE configurat ion in the NVRAM by f irst settin g up
the current configuration and then sending an AT&Wn command. The DCE configuration stored
in the NVRAM is called a user profile . Two independent us e r profile configu rations and four
telephone numbers can be stored. Either user profile configuration can be used for the power-up
defaults (AT&Yn). While in command mode, the DCE can be re-initialized at any time and the
user profile c hanged using the ATZn command. To configure the modem to fact ory defaults, t he
AT&F command is used. A summary of the active user profile, two NVRAM user profiles, and
previously-saved tele phone numbers can be read from the modem using the view command,
AT&Vn. The AT&Zn=x command stor e s one of four telephone numbers in the NVRAM. To dial
these telephone numbers, use the ATDS=m command.

If the active profile is not stored in one of the two user pr ofiles af ter set ting up the modem, then the
current settings are lost when the commands ATZ or AT&F are issued or when the modem is
powered down.

Examples:

ATZ Resets and then configures the modem to NVRAM user profile 0.
AT&F S0=1 &W1 &F configures the modem for facto ry defaults.

&Y1

S0=1 configures the modem to answer after one ring.
&W1 saves the active configuration to user profile 1.
&Y1 configures the modem to use NVRAM user profile 1 as the

power-up defaults.

AT&Z2 = 9, Stores a telephone number into the NVRAM as phone number 2 , w hich
[phone] can be re-dialed later using ATDS=2.

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Data Mode AT COMMANDS

3.4 Modem Identification Commands [In, +FMI, +FMR,
+FMM, +GMI, +GMM, +GMR, +GSN,
+FMFR?, +FMDL?, +FREV?]

The modem provides product identification AT commands that help determine the modem’s
manufac t urer, m ode l number, and product re vision. To provide flexibility with older software
application programs, the modem supports several co mm a nds that can be us e d to request a single
item of identification (such as a modem mode l num ber). Table 15 lists the commands used to
obtain product information (all identification comma nds are usable in data, fax, or voice mode).

Table 15. Product Identification Information

AT Commands

Product Information ATIn Command Data Mode Class 1 Fax Mode Legacy Modems

Modem Manufacturer ATI2 AT+GMI AT+FMI AT+FMFR?
Model ID ATI1 AT+GMM AT+FMM AT+FMDL?
Revision Number ATI4 AT+GMR AT+FMR AT+FREV?

Example:

ATI1 Causes the modem to send the modem’s name to the DTE.
Intel 536EP Respon se to the m o de m na me reques t .

V.92 Modem

3.5 Establishing a Modem Connection [A, D, DS = n, S0]

Data mode provi des seve ral met hod s for es tab lishi ng a conn ec ti on with a remote m odem. For ea ch
modem, a connection can be init iated manually or automatically in both answer and originate
modes. A manual-to- manual connection is useful when both modems (that are on-hook) are
connected to an off-hoo k telephone line. For example, if two people are talking on the telephone,
they can man ua l ly establish a mo de m connection without first hanging up. When establishing a
manual connection, one mo dem must b e des ignated as the originating modem and the oth er as the
answering modem. Manual originate mode is initiated by sending a n ATD to the DCE. Manual
answer mode is accomplished by sending an ATA to the DCE.

Automatic originate mode is initiated by sending an ATD <telephone number & dial modifiers>
or ATDS=m to the DCE. Automatic-answer mode is accomplished by setting S-register S0 to a
non-zero va lue. S1 keeps track of how many ring signals are detected. If the content of S0 is non-
zero and the num ber of r ing signa l s (as define d by S0) ar e detected (that is, S1 = S0), then the DCE
goes off- hook and attempts to conne ct to the remote modem (with the following exceptions):

• The time period between th e ring signals is greater than 8 seconds, which causes the S1

counter to rese t and thus never re a ch the value for S0.

• Caller ID is enabled and S0=1, the modem an swers on the second ring signal instead of the

first ring signal. This happens because Calle r ID puts a signal on t he telephone line between
the first and second ring signal.

Example:

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Data Mode AT COMMANDS

ATDT 9,444-5555 Automatical ly dials the telephone nu mber with DTMF tones. After

dialing a ‘9’, the comma (,) causes the modem to pa use two seconds
before d i a l ing the rest of the te lephone numbe r.

modem 1: ATD; When establishing a manual-to- manual connection, the designated
modem 2: ATA originating modem should receive the ATD command from its DTE

just before the designa ted answering modem receives the ATA
command from its DTE. It is important that the time between the ATD
and ATA commands is less than 2 seconds.

AT-C1DT 123 Causes the modem to dial the telephone number 123 and immediately

start sending a data calling tone. Calling tone can then be detected by
the remote voice mail system. After detecting the calling tone, the
remote system can change to data mode and start the data mo dem
connection handshake.

3.6 Online Command Mode [Escape Codes, On]

After establishing a connection with a remote modem, the DTE sends the appropriate escape
sequence to the DCE, which causes the DCE to enter the online command mode. The online
command mode is used to send AT commands to the DCE while the DCE is still connected to the
remote modem. The supported e scape sequences a re described in Section 3.10, “AT Escape

Sequences” on page 38. To re-enter the online data mode, use the ATOn command .

Example:

1 second +++ Hayes Escape Sequence. Guard times (in which the DTE does not send
1 second data to the DCE) of 1 second are needed before and after the three

escape characters ‘+’.

+++AT<CR> TIES (Time Independent Escape Sequence).
ATO Causes the modem to re-e nter online data mode.

3.7 H anging Up [Hn, S10, Zn, &D2]

A modem connec tion termina te s when the modem hangs up or when the remote modem transmit
carrier is off longer than the duration specified in S-register S10. To hang up, the DTE ty pically
sends an escape code sequence that causes the DCE to enter online command mode. Upon
receiving a n ‘OK’ message, the DTE sends either ATH or ATZn to the DCE. When the AT&D2
command is used, the modem goes on- hook (hangs up) afte r an on-to-of f transition of the DTR
occurs.

Note: The ATZn command causes the DCE to hang up and re-in itia lize itse lf to the user profil e specif ied

by ‘n’.

3.8 Modem-to-Modem Connection Data Rates

The data rates differ for each data mode selected. The 536EX chipsets either default to V.90 or V.92
mode depending on the driver version. For non-ISP connections, the chipsets f a ll back to V.34
mode. The modem defaults to whatever mode is is su ed by the +MS=m command (see the
supported modulation types on Table16 on page 35).

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