Contents:
Welcome to 56K Information Access
Installation for All Operating Systems
Technical Reference >
Introduction to Syntax and Procedures
Data Command Set
- Generic Modem Commands
- DTE Interface
- Call Control
- Modulation Control Commands
- Error Control Commands
- Data Compression Commands
- Diagnostic Commands
- V.92 +P Commands
- S Parameters
Result Codes
Call Control
D - Dial
This command directs the modem to go on-line, dial according to the string entered and attempt to establish a connection. If no dial string is supplied, the modem will go on-line and attempt the handshake in originate mode.
Note: If the ATD command is issued before the S1 register has cleared, the modem will respond with the NO CARRIER result code.
If +FCLASS=0 is selected, the modem will behave as a data modem and will attempt to connect to another data modem. The modem will have up to the period of time specified by register S6 or S7 to wait for carrier and complete the handshake. If this time expires before the modem can complete the handshake, the modem will go on-hook with the NO CARRIER response. This command will be aborted in progress upon receipt of any DTE character before completion of the handshake.
If +FCLASS=1, 1.0, or 2 is selected, the modem will behave as a facsimile modem and attempt to connect to a facsimile machine (or modem) by entering the HDLC V.21 channel 2 receive state (as if +FRH=3 had been issued). This command will be aborted upon receipt of any DTE character if the modem has not finished dialing. In this case, the modem will go on-hook and return to command mode after displaying the NO CARRIER message. If the modem has finished dialing, it proceeds as if the +FRH=3 command has been issued. (Refer to the +FRH command to determine how the modem behaves following this stage.)
Dial Modifiers
The valid dial string parameters are described below. Punctuation characters may be used for clarity, with parentheses, hyphen, and spaces being ignored.
Syntax
D
Defined Values
<string> Character string corresponding to the selected option(s).
|
0-9
|
DTMF digits 0 to 9. |
|
*
|
The 'star' digit (tone dialing only). |
|
#
|
The 'gate' digit (tone dialing only). |
|
A-D
|
DTMF digits A, B, C, and D. Some countries may prohibit sending of these digits during dialing. |
|
L
|
Re-dial last number: the modem will re-dial the last valid telephone number. The L must be immediately after the D with all the following characters ignored). |
|
L?
|
The ATDL? will transmit the last number dialed to the DTE. |
|
P
|
Select pulse dialing: pulse dial the numbers that follow until a "T" is encountered. Affects current and subsequent dialing. Some countries prevent changing dialing modes after the first digit is dialed. |
|
T
|
Select tone dialing: tone dial the numbers that follow until a "P" is encountered. Affects current and subsequent dialing. Some countries prevent changing dialing modes after the first digit is dialed. |
|
R
|
This command will be accepted, but not acted on. |
|
S=n
|
Dial the number stored in the directory (n = 0 to 3). (See &Z.) |
|
!
|
Flash: the modem will go on-hook for a time defined by the value of S29. Country requirements may limit the time imposed. |
|
W
|
'W' dial parameter handling modified based on X setting. When the modem is configured in X0, X1, or X2 then 'W' converts to delay ','. |
|
@
|
Wait for silence: the modem will wait for at least 5 seconds of silence in the call progress frequency band before continuing with the next dial string parameter. If the modem does not detect these 5 seconds of silence before the expiration of the call abort timer (S7), the modem will terminate the call attempt with a NO ANSWER message. If busy detection is enabled, the modem may terminate the call with the BUSY result code. If answer tone arrives during execution of this parameter, the modem handshakes. |
|
&
|
Wait for credit card dialing tone before continuing with the dial string. If the tone is not detected within the time specified by S7 (US models) or S6 (W-class models), the modem will abort the rest of the sequence, return on-hook, and generate an error message. |
|
,
|
Dial pause: the modem will pause for a time specified by S8 before dialing the digits following ",". |
|
;
|
Return to command state. Added to the end of a dial string, this causes the modem to return to the command state after it processes the portion of the dial string preceding the ";". This allows the user to issue additional AT commands while remaining off-hook. The additional AT commands may be placed in the original command line following the ";" and/or may be entered on subsequent command lines. The modem will enter call progress only after an additional dial command is issued without the ";" terminator. Use "H" to abort the dial in progress, and go back on-hook. |
|
^
|
Toggles calling tone enable/disable: applicable to current dial attempt only. |
|
()
|
Ignored: may be used to format the dial string. |
|
-
|
Ignored: may be used to format the dial string. |
|
<space>
|
Ignored: may be used to format the dial string. |
|
<i>
|
Invalid character: will be ignored. |
|
>
|
If enabled by country specific parameter, the modem will generate a grounding pulse on the EARTH relay output. |
|
"
|
When dial parameter " encountered all subsequent alpha characters (a-z or A-Z) will be decoded as a number from a standard telephone handset. |
|
/
|
This dial parameter invokes a short delay of 125ms before proceeding. |
T - Set Tone Dial Default
This command forces DTMF dialing until the next P dial modifier or P command is received. The modem will set an S-Parameter bit to indicate that all subsequent dialing should be conducted in tone mode. The DP command will override this command. Clears S14 bit 5. This command may not be permitted in some countries. (See P.)
Result Code
OK
P - Set Pulse Dial Default
This command forces pulse dialing until the next T dial modifier or T command is received. Sets S14 bit 5.
As soon as a dial command is executed which explicitly specifies the dialing mode for that particular call (e.g., ATDT...), this command is overridden so that all future dialing will be tone dialed. (See T command.) This command may not be permitted in some countries.
Result Code
OK
A>
Repeat the last command once every S6 seconds. Repeat cycle terminated if any key pressed. The aborting key press is not processed or speed sensed. If last command is connection attempt 'D','A', or 'O' then A> acts like A/.
A - Answer
The modem will go off-hook and attempt to answer an incoming call if correct conditions are met. Upon successful completion of answer handshake, the modem will go on-line in answer mode. This command may be affected by the state of Line Current Sense, if enabled. (Most countries do not require Line Current Sense.) Operation is also dependent upon +FCLASS command and country-specific requirements.
If +FCLASS=0 is selected, the modem will enter the connect state after exchanging carrier with the remote modem. If no carrier is detected within a period specified in register S7, the modem hangs up. Any character entered during the connect sequence will abort the connection attempt.
If +FCLASS=1, 1.0, or 2 is selected, the modem will go off-hook in V.21 answer mode. It will generate the V.21 2100 Hz answer tone for 3 ± 0.5 seconds and, following a delay of 70 ms, will proceed as if the +FTH=3 command were issued. At any stage up to (but excluding) the +FTH=3 command state, any character will abort the communication. (See the description of the +FTH command for details.)
H - Disconnect (Hang-Up)
This command initiates a hang up sequence. This command may not be available for some countries due to PTT restrictions.
Syntax
H<value>
Defined Values
<value> Decimal number corresponding to the selected option.
|
0
|
The modem will release the line if the modem is currently on-line, and will terminate any test (AT&T) that is in progress. Country specific, modulation specific, and error correction protocol specific (S38) processing is handled outside of the H0 command. |
|
1
|
If on-hook, the modem will go off-hook and enter command mode. For US models, the modem will remain off-hook. For W-class models, the modem will return on-hook after a period of time determined by S7. |
Result Codes
|
OK
|
<value> = 0 or 1. |
|
ERROR
|
Otherwise |
O - Return to On-Line Data Mode
This command determines how the modem will enter the on-line data mode. If in the on-line command mode, the modem enters the on-line data mode with or without a retrain. If in the off-line command mode (no connection), the modem reports ERROR.
Syntax
O<value>
<value> Decimal number corresponding to the selected option.
|
0
|
Enters on-line data mode without a retrain. Handling is determined by the Call Establishment task. Generally, if a connection exists, this command connects the DTE back to the remote modem after an escape (+++). |
|
1
|
Enters on-line data mode with a retrain before returning to on-line data mode. |
|
2
|
Fast retrain without speed change (used for diagnostic purpose only). |
|
3
|
Renegotiate rate without speed change (used for diagnostic purpose only. |
|
4
|
Renegotiate rate down one speed (used for diagnostic purpose only). |
|
5
|
Renegotiate rate up one speed (used for diagnostic purpose only). |
Result Codes
|
OK
|
<value> = 0 to 5 and a connection exists. |
|
ERROR
|
Otherwise or if not connected. |
L - Speaker Volume
This command sets the speaker volume control. The parameter value, if valid, is written to S22 bits 0 and 1.
Syntax
L<value>
<value>
|
0
|
Low volume. |
|
1
|
Low volume: (Default) |
|
2
|
Medium volume. |
|
3
|
High volume. |
Result Codes
|
OK
|
<value> = 0 to 3. |
|
ERROR
|
Otherwise |
M - Speaker Control
This command selects when the speaker will be on or off. The parameter value, if valid, is written to S22 bits 2 and 3.
Syntax
M
Defined Values
<value> Decimal number corresponding to the selected option.
|
0
|
Speaker is always off. |
|
1
|
Speaker is on during call establishment, but off when receiving carrier. (Default.) |
|
2
|
Speaker is always on. |
|
3
|
Speaker is off when receiving carrier and during dialing, but on during answering. |
Result Codes
|
OK
|
<value> = 0 to 3. |
|
ERROR
|
Otherwise |
&G - Select Guard
This command causes the modem to generate the guard tone selected by this command (DPSK modulation modes only). The parameter value, if valid, is written to S23 bits 6 and 7.
Syntax
&G
Defined Values
<value> Decimal number corresponding to the selected option.
|
0
|
Disables guard tone. (Default.) |
|
1
|
Disables guard tone. |
|
2
|
Selects 1800 Hz guard tone.This command may not be permitted in some countries |
Result Codes
|
OK
|
<value> = 0 to 2. |
|
ERROR
|
Otherwise |
*B - Display Blacklisted Numbers
This command requests the modem to return a list of blacklisted numbers to the DTE. The format of the response is shown by the example below. Permanently forbidden numbers as defined by country requirements will not appear on this list. If no numbers are blacklisted, only the OK result code is issued.
Syntax
*B
Example
NO. - PHONE NUMBER - ------ ------------------------------
1; 4175537660
2; 8288924961
3; 3887278862
4; 3124839442
5; 6284664
OK
