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Chapter 5 – Call Control Commands
Multi-Tech Systems, Inc. Wireless GSM/GPRS AT Commands (Document Number S000293I) 19
Chapter 5 – Call Control
Commands
Dial Command D
Description: The ATD command sets a voice or data call. As per GSM 02.30, the dial command also controls
supplementary services.
Data Calls
For a data call, the application sends the following ASCII string to the product (the bearer must be
previously selected with the +CBST command):
ATD<nb> where <nb> is the destination phone number. Note: If a GPRS PPP session is already
running, the setting of CSD (GSM data call) is not supported.
Voice Calls
For a voice call, the application sends the following ASCII string to the product: (the bearer may be
selected previously, if not a default bearer is used).
ATD<nb>; where <nb> is the destination phone number.
Emergency Calls
For emergency calls:
These Emergency Numbers are available without
a SIM card:
000, 08, 110, 112, 118, 119, 911 and 999.
These Emergency Numbers are available with a SIM card:
When EF_ECC file is missing from SIM: 112 and 911.
When SIM includes an EF_ECC file: 112, 911 and any emergency numbers available in the
EF_ECC file.
International Numbers
For an international number, the local international prefix does not need to be set (usually 00) but does
need to be replaced by the ‘+’ character.
Example: to set up a voice call to Multi-Tech offices from another country, the AT command is:
“ATD+17637853600;”
Some countries/regions may have specific numbering rules for their GSM handset numbering.
Values: <nb> Destination phone number
<I> Optional parameter.
<I> means “invocation” (restrict CLI presentation)
<i> means “suppresssion” (allow CLI presentation)
<mem> Phonebook (one of SM, LD, MC, ON, ME, RC, MT or SN). A default value can be selected
by using the +CPBS command.
<index> Call number at indicated offset from the phonebook selected by the +CPBS command.
<name> Call number corresponding to given name from the phonebook selected by the +CPBS
command.
The response to the ATD command is one of the following:
V
erbose result code Numeric code
(with ATV0 set)
Description
OK 0 if the call succeeds, for voice call only
CONNECT <speed> 10,11,12,13,14,15 if the call succeeds, for data calls only, <speed> takes
the value negotiated by the product.
BUSY 7 If the called party is already in communication
NO ANSWER 8 If no hang up is detected after a fixed network time-out
NO CARRIER 3 Call setup failed or remote user release. Use the
AT+CEER command to know the failure cause