Specifications

Chapter 7 – Call-Related Commands
Multi-Tech Systems, Inc. AT Commands for EDGE Modems (S000371B) 75
7.2 ATA Answer a Call
Description: TA causes remote station to go off-hook (e.g., answer call).
Exec Command Syntax: ATA
Response: In case of data call, if successfully connected (TA switches to data mode):
CONNECT <text>
In case of voice call, if successfully connected: OK
When TA returns to command mode after call release: OK
If no connection: NO CARRIER
Parameter Description:
<text>
Connection status
<text> output only if ATX parameter setting with value greater 0.
Notes
• Any additional commands on the same command line are ignored.
• The command may be aborted generally by receiving a character during execution. It can’t be aborted in some
connection setup states, such as handshaking.
• If AT+FCLASS setting is 1 or 2, all incoming calls will be answered as fax calls, when ATA is issued on
multiplexer channel 1 resp. ASC0. For calls explicitly signalled as voice or data calls, this procedure will fail with
result code “NO CARRIER”, but the call in question will continue to ring. It is possible to change the setting for
AT+FCLASS to 0 while the call is ringing, and accept the call normally afterwards with ATA.
• The ATA command may be used also to accept a network request for a PDP context activation (see ATA).
• See also ATX for <text>.
• If an incoming call is no longer available (already disconnected/hang up), a “NO CARRIER” result code will be
given.
7.3 ATD Mobile Originated Call to a Specified
Number
Description: This command can be used to set up outgoing voice, data or fax calls. It also serves to control
Supplementary Services. The termination character “;” is mandatory to set up voice calls or to
send *# codes for Supplementary Services. It must not be used for data and fax calls.
Additional notes on the responses returned after dialing with ATD:
• For voice calls, you have the choice of two different response modes that can be selected
with AT^SM20:
AT^SM20=1 (factory default) causes the ME to respond once the call setup is completed
either successfully (“OK”) or unsuccessfully (“NO CARRIER”, “NO DIAL TONE”, “BUSY”).
AT^SM20=0 causes the ME to return “OK” immediately after dialing was completed (i.e.,
before call setup terminates successfully or unsuccessfully).
• For data connections, call setup always terminates when the call has been established
(indicated by the result code “CONNECT <text>), or when it fails (indicated by “NO
CARRIER”). The settings of AT^SM20 do not apply.
Different call release indications:
• Upon termination, an outgoing fax or data call may show a different result code than a voice
call would show under identical conditions. In order to track down the actual reason for call
termination, AT+CEER or ATS18 should be used for all applicable connections.
Using ATD during an active call:
• When a user originates a second voice call whil there is already an active voice call, the first
call will automatically put on hold. The second call attempt is acknowledged with “OK”
immediately after dialing with ATD has completed, without relation to a successful call setup.
In case of failure, the additional result codes “NO CARRIER”, “NO DIAL TONE”, “NO
CARRIER” will be presented afterwards (see example below).
Exec Command Syntax: ATD<n>[<mgsm>][;]
Response: If no dialtone (parameter setting ATX2 or ATX4): NO DIALTONE
If busy (parameter setting ATX3 or ATX4): BUSY
If a connection cannot be set up: NO CARRIER
OK
If successfully connected and non-voice call (TA switches to online data mode):
CONNECT <text>
When TA returns to command mode after call release: OK
If successfully connected and voice call: OK