Specifications

Chapter 7 – Call-Related Commands
Multi-Tech Systems, Inc. AT Commands for EDGE Modems (S000371B) 88
Notes:
• Teleservices other than voice, data, fax are not fully supported by ME. They are used only in connection with
the handling for AT+CSNS, and may therefore occur in parameter <mode> for mobile terminated calls.
• If a URC “^SLCC” in verbose mode (see AT^SCFG) has been buffered while the interface was in dedicated
mode (depending on the settings of AT+CMER parameter <bfr>), each buffered event indicator will be output
as a separate URC after the interface returns to idle mode.
• However, the output will deliver the list of current calls in the “current” state (at the time when the output is
generated), possibly leading to multiple displays of identical list configurations.
• Some parameters of AT command AT+CHLD, as well as some situations where the call status in the network
changes very quickly (e.g., the transition between <stat>= “unknown”, “dialing” and “alerting” for a call to a
reachable subscriber within the registered network) may lead to quasi-simultaneous changes to the states of
one or several calls in the list, possibly leading to multiple displays of identical list configurations.
• If multiple displays of identical list configurations occur, this happens because of intermediate states of the list,
that have already been overridden by new transitions and states. Thus, it is guaranteed that the configuration
displayed in such cases is the current configuration at the time of the last display.
• It is adviseable to receive URC “^SLCC” on an interface that is not used for call initiation, if verbose output is
configured. If only voice calls are expected, a setting of AT^SM20= 0 may be used alternatively in order to
keep the call from blocking the interface.
Examples
Example 1
^SYSSTART
at+cpin=9999
OK
+CREG: 2
+CREG: 1,”0145”,”0016” We are now registered
at^sm20=0 command “ATD” for an outgoing voice call will terminate immediately with
response “OK”
OK
atd”1234567”; We start a voice call.
OK “OK” response is issued immediately because of setting “^SM20=0”
^SLCC: MO call starts, paging B-party
1,0,2,0,0,0,”1234567”,129,”Called Party”
^SLCC: End of current list
^SLCC: Traffic channel established,
1,0,2,0,0,1,”1234567”,129,”Called Party” network may now transmit network announcements,
ME may now transmit DTMF tones.
^SLCC: End of current list
^SLCC: Call is now ringing at B-Party
1,0,3,0,0,1,”1234567”,129,”Called Party”
^SLCC: End of current list
^SLCC: B-Party has accepted the call, connection established
1,0,0,0,0,1,”1234567”,129,”Called Party”
^SLCC: End of current list
atd23456; We start a second voice call.
OK “OK” response issued immediately because another call is already active (ATD)
^SLCC: The active call is automatically put on hold, triggering the display of the list
1,0,1,0,0,0,”1234567”,129,”Called Party”
^SLCC: 2,0,2,0,0,1,”23456”,129 The second call has already started before the indication for the held call could
be displayed
^SLCC: End of current list
^SLCC: Identical list is displayed again, triggered by the start of the second voice call
^SLCC: 2,0,2,0,0,1,”23456”,129 Status of the second list entry has already been displayed with the previous URC
^SLCC: End of current list
^SLCC: The held call doesn’t change status right now
1,0,1,0,0,0,”1234567”,129,”Called Party”
^SLCC: 2,0,3,0,0,1,”23456”,129 The second call is now alerting the B-Party
^SLCC: End of current list
^SLCC: The held call doesn’t change status right now
1,0,0,0,0,1,”1234567”,129,”Called Party”
^SLCC: End of current list: the B-Party of the second call has not accepted the call in
time, the second call has ended.
NO CARRIER The second call has ended
^SLCC: list is now empty: B-Party has ended the first call
NO CARRIER The first call has ended