MC55 AT Command Set
7. Call related Commands s
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MC55_ATC_V01.05 Page 137 of 469 2/10/04
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7. Call related Commands
The AT Commands described in this chapter are related to Mob ile Originated (MOC, i.e. outgoing) Calls and
Mobile Terminated (MTC, i.e. incoming) Calls.

7.1 Call Status Information

For Circuit switched calls, including voice, fax and data ca lls, call status information is available with URC
''"+CIEV": call'' (configurable via AT commands AT+CIND and AT+CMER) or - in more detail - from the list of cur-
rent calls. This list can be displayed on request via at commands AT+CLCC and AT^SLCC. It can also be issued
by the ME in the form of an unsolicited result code "^SLCC" if configured with AT^SLCC and AT+CMER.
URC ''"+CIEV": call'' and URC "^SLCC" can be configured using AT command AT^SCFG. An overview of the pos-
sible configurations and their consequences for the availability of cal l status information will be given here.
Generally speaking, the call status values recognized by the ME are as follows:
•active
• held
• dialing (MOC)
• alerting (MOC)
• incoming (MTC)
• waiting (MTC)
• terminating: The call is not active anymore, but inband information i s still available.
• dropped: The call has been suspended by the network, but may be resumed later.
The values "terminating" and "dropped" are not standardized for AT command AT+CLCC, and therefore on ly
available for command AT^SLCC. A call in any of these two states will not appea r in the list of current calls as
displayed with AT+CLCC.
A call that is not recognized by the ME is considered to be in "unknown " state.
Some networks may schedule a traffic channel for a call that is not yet in the "active" state. This i s reflected in
parameter <traffic channel assigned> of AT command AT^SLCC and the corresponding URC.
Depending on the value of AT^SCFG setting <succ>, Indicator "+CIEV" will be issued (if configured with
AT+CIND and AT+CMER)
• when a state transition ends in state "active" or in state "unknown"
(if AT^SCFG setting <succ>=''restricted'').
• when any state transition (including transitions beginning or ending in state "unknown") occu rs in the list of
active calls, or when a traffic channel is established
(if AT^SCFG setting <succ>=''verbose'').
The indicator value for indicator ""+CIEV":call" will be "1" if at leas t one call is in states "held" or "active", and "0"
otherwise.
Depending on the value of AT^SCFG setting <sucs>, Indicator "^SLCC" will be issued (if configured with write
command AT^SLCC and AT+CMER)
• when a state transition ends in state "active" or in state "unknown" (if AT^SCFG setting <sucs>="restricted")
• when any state transition (including transitions beginning or ending in state "unknown") occu rs in the list of
active calls, or when a voice channel is established (if AT^SCFG setting <sucs>="verbose").
Due to compatibility considerations, the powerup default for AT^SCFG setting <succ> is "restricted", offering
compatibility to the standard behaviour of indicator ''"+CIEV": call'', while th e default for setting <sucs> is "ver-
bose".