Data Mode AT COMMANDS

Table 18. Data Mode Command Descriptions (Continued)

Command

Default

 

Description

 

 

 

 

 

Long Space Disconnect: This command determines whether the modem disconnects after receiving

 

 

1.6 seconds of silence and whether the modem sends a period of silence to the remote modem before

 

 

disconnecting.

Yn

0

n = 0*

Disables long space disconnect

 

 

n = 1

Enables long space disconnect. The modem disconnects after receiving 1.6 seconds of

 

 

 

silence from the remote modem. Additionally, after receiving an ATH0 command, the

 

 

 

modem sends at least 4 seconds of silence before hanging up.

 

 

 

 

 

Reset Modem/Recall Stored Profile: This command causes the modem to go on-hook (hang-up),

 

 

perform a warm reset, and load user-configuration profile ‘n’ (previously stored in the NVRAM) into the

Zn

0

active profile. The Zn command must be the last command in command string, as it causes all

subsequent commands to be ignored.

 

 

n = 0*

Resets the modem and recalls user profile 0

 

 

n = 1

Resets the modem and recalls user profile 1

 

 

 

 

 

DCD (Data Carrier Detect) Option: This command controls how the modem functions in relation to the

 

 

DCD or RLSD signal.

&Cn

1

n = 0

State of carrier from remote modem is ignored. DCD is always on.

 

 

n = 1*

State of carrier from remote modem is tracked. DCD reflects the state of the received

 

 

 

carrier.

 

 

 

 

 

DTR (Data Terminal Ready) Option: This command controls how the modem responds to DTR. After

 

 

toggling DTR, the host should wait 200 ms before modifying the UART registers or sending a new

 

 

command to the modem. This is done because the modem does not send an ‘OK’ message to indicate it

 

 

has performed the requested function.

 

 

n = 0

In asynchronous mode (&Q0), the modem ignores DTR.

&Dn

2

n = 1

The modem switches from data mode to command mode when an on-to-off transition of

 

DTR occurs.

 

 

 

 

 

n = 2*

An on-to-off transition of DTR causes the modem to go on-hook (hang up). While DTR is

 

 

 

off, auto-answer is disabled.

 

 

n = 3

An on-to-off transition of DTR re-initializes the modem. The re-initialize procedure performs

 

 

 

the same function as a power-up reset, except that the UART registers are not

 

 

 

reconfigured.

 

 

 

&F

none

Load Factory Defaults: This command loads command defaults and S-register factory defaults into the

active configuration and configures the modem for data mode.

 

 

 

 

 

 

 

Guard Tone Option: This command controls whether the modem sends out guard tones while

 

 

connected to a remote modem (for ITU-T V.22 bis [1200 bps] and V.22 bis [2400 bps] connections only).

 

 

Guard tones may be required in some countries but are not needed in the United States. Guard tones are

&Gn

0

sent by the answer modem to disable Central Office echo cancelers.

n = 0*

Guard tone disabled

 

 

 

 

n = 1

550 Hz guard tone enabled

 

 

n = 2

1800 Hz guard tone enabled

 

 

 

 

 

Select Serial Port Flow Control: This command specifies the DTE-to-modem flow control. Software

 

 

flow control uses the characters XOFF (13h) and XON (11h) to stop and start data transmission,

 

 

respectively, both to and from the DTE. Bidirectional hardware flow control uses RTS/CTS to stop and

&Kn

3

start data from the modem.

n = 0

Disables flow control

 

 

 

 

n = 3*

Bidirectional hardware flow control—RTS/CTS

 

 

n = 4

XON/XOFF software flow control

 

 

 

 

NOTE: An asterisk (*) denotes the factory-default setting.

44

536EX Chipset Developer’s Manual

Intel Confidential

Page 44
Image 44
Intel 537EX Disconnecting, Modem sends at least 4 seconds of silence before hanging up, Subsequent commands to be ignored

537EX specifications

The Intel 537EX is a powerful and innovative embedded processor designed for a range of applications, particularly in the fields of industrial automation, telecommunications, and transport management systems. This processor is a member of Intel's embedded product line, tailored specifically to meet the demands of systems that require high reliability and long lifecycle support.

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