Siemens MC55 AT manual Call related Commands, Call Status Information, AT+CIND and AT+CMER

7.Call related Commands

The AT Commands described in this chapter are related to Mobile Originated (MOC, i.e. outgoing) Calls and Mobile Terminated (MTC, i.e. incoming) Calls.

7.1Call Status Information

For Circuit switched calls, including voice, fax and data calls, 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 current 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 call 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 is 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 only available for command AT^SLCC. A call in any of these two states will not appear 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 is 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") occurs 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 least 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") occurs 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 the default for setting <sucs> is "ver- bose".

In order to see the URCs, event reporting for both indicators must be explicitely configured with the appropriate AT commands.

MC55_ATC_V04.00	Page 126 of 475	3/17/06
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