Specifications

3GPP
3GPP TS 27.007 V6.3.0 (2003-
06)
2
7
Release 6
VOICE DATA
HANGUP
AT+CHUP or
remote initiated hangup
AT+CHUP or
remote initiated hangup
(or ATH
or drop DTR)
ATD or ATA or
remote initiated
ATH or drop DTR or
remote initiated
ATDxxxATDxxx;
AT+CMOD=2
AT+FCLASS=0
TA sets +CMOD=0
+CRING: ALT VOICE/XXX
AT+CMOD=2;+FCLASS=0
+CRING: ALT XXX/VOICE
AT+CMOD=2;+FCLASS=0
MT voice first
MT data first
MO
ATA
ATA
Figure 5: Alternating voice and data call
Voice/ fax call (teleservice number 61)
Figure 6 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. The parameter "x" of +FCLASS command can be 1, 1.0, 2 or 2.0.
NOTE: The transition from fax mode to voice mode is for further study.
VOICE FAX
HANGUP
ATD or
remote initiated
ATDxxxATDxxx;
AT+CMOD=1
AT+FCLASS=x
TA sets +CMOD=0
+CRING: ALT VOICE/FAX
AT+CMOD=1;+FCLASS=x
+CRING: ALT FAX/VOICE
AT+CMOD=1;+FCLASS=x
MT voice first
MT fax first
MO
ATA
ATA
refer ITU-T T.31 [11] and T.32 [12]
for different hangup possibilities
(also AT+CHUP shall hangup)
AT+CHUP or
remote initiated hangup
(or ATH
or drop DTR)
Figure 6: Alternating voice and fax call
6.7 Select bearer service type +CBST
Table 14: +CBST parameter command syntax
Command
Possible response(s)
+CBST=[<speed>[,<name>[,<ce>]]]
+CBST?
+CBST: <speed>,<name>,<ce>