Command

Function and Description

&D

Data Terminal &D determines how the modem responds to the DTR signal from the terminal. The country

Ready Options configuration may prevent the modem from detecting terminal DTR. In this case, the

modem assumes DTR is always on. In North America, terminal DTR is normally detected. If DTR detection

has been prevented, the modem will respond with an ERROR result to this command.

The response to changes in DTR also depends on the &Q and &D commands. This table defines what

happens when DTR goes off for all possible combinations of the &D and &Q commands. To see what

happens when DTR goes on refer to the &Q command. The default value is &D0 in North America:

&D0

&D1

&D2

D3

&Q0

None

B

C

D

&Q1

A

B

C

D

A

The modem hangs up the telephone line and issues an OK result code.

B

If in the On-Line state, the modem goes into the Command state and issues an OK result code.

C

The modem hangs up the telephone line and issues an OK result code. Auto-Answer is disabled as

long as DTR stays off.

D

The modem resets.

E

Command Mode E tells the modem whether or not to echo characters sent from the terminal when the

modem is Character Echo accepting AT commands.

E0

Does not echo characters sent from the terminal.

E1

Echo characters sent from the terminal. This is the default value in North America.

%E

Automatic Retrain

The %E command controls whether the modem will initiate retrain with the other modem during

Options

a telephone line connection during operation in data modes supporting retrain. The modem always

responds to a retrain operation initiated by the remote modem. The modem can be forced to initiate a

retrain by the On-Line (O1) command.

%E0

Do not initiate a retrain.

%E1

Initiate a retrain if the datapump indicates one is required.

&F

Recall Factory

&F changes these AT command options and S-registers to their default values. The default

Profile

values may be changed for use in different countries. The values for North America are:

S-registers

S0=0 S1=0

S2=43

S3=13

S4=10

S5=8

S6=2 S7=30

S8=2

S9=6

S10=14

S11=95

S12=50

S17=10

S25=5

S28=0

S29=25 S37=0

Commands

B1

E1

M1

P

Q0

V1

X4

&C0

&D0

&G0

&P0

&Q0

%E1

&G

Guard Tone Options

&G tells the modem which guard tone to transmit when the modem is transmitting the high band (i.e.,

answer handshake and answer mode).

&G0

No guard tone. This is the default value in North America.

&G1

550 Hz guard tone (V.22 and V.22bis only)

&G2

1800 Hz guard tone (V.22 and V.22bis only)

CPC2400E

www.clare.com

9

Rev. 2

AT Command Set