Specifications

3GPP

3GPP TS 27.007 V6.3.0 (2003-

06)

Release 6

6.6 Alternating mode call control method

This subclause describes the procedure to handle alternating mode calls with AT commands. Procedures are mandatory

when alternating mode calls are implemented in the TA.

NOTE: ATH and drop DTR will not necessarily cause a hangup from voice mode. If the +CVHU is implemented

the behaviour shall be controlled by its setting.

Voice followed by data call (bearer service 81)

Figure 4 shows commands to start the call, to switch from voice to data (In-Call Modification) and to hang up the call.

+CMOD and +FCLASS commands indicate the current settings before dialling or answering command, not that they

shall be given just before D or A command. Refer subclause "Cellular result codes +CRC" for possible +CRING result

code values. Refer Annex F for a detailed example.

VOICE DATA

HANGUP

AT+CHUP or

remote initiated hangup

(or ATH

or drop DTR)

ATD or ATA or

remote initiated

ATDxxx;

AT+CMOD=3

AT+FCLASS=0

TA sets +CMOD=0

+CRING: VOICE/XXX

AT+CMOD=3;+FCLASS=0

ATH or

drop DTR or

AT+CHUP or

remote initiated hangup

ATA

Figure 4: Voice followed by data call

Voice/ data call (bearer service number 61)

Figure 5 shows the commands to start the call, to switch between modes (In-Call Modification) and to hang up the call.

+CMOD and +FCLASS commands indicate the current settings before dialling or answering command, not that they

shall be given just before D or A command. Refer subclause "Cellular result codes +CRC" for possible +CRING result

code values. Refer Annex E for a detailed example.