6 Call control commands and methods

27.0073GPPAT command set for User Equipment (UE)Release 18TS

6.0 General

This clause describes the control of calls. Normal data and fax call control is done as in ITU‑T Recommendation V.250 [14], ITU‑T Recommendation T.31 [11] and ITU‑T Recommendation T.32 [12]. For voice call originating, refer clause "ITU‑T Recommendation V.250 dial command D" and clause "Commands for enhanced support of dialling".

6.1 Select type of address +CSTA

Table 11: +CSTA parameter command syntax

Command	Possible response(s)
+CSTA=[<type>]
+CSTA?	+CSTA: <type>
+CSTA=?	+CSTA: (list of supported <type>s)

Description

Set command selects the type of number for further dialling commands (D) according to 3GPP TS 24.008 [8].

Read command returns the current value of <type>.

Test command returns values supported as a compound value.

Defined values

<type>: type of address octet in integer format (refer 3GPP TS 24.008 [8] clause 10.5.4.7); default 145 when dialling string includes international access code character "+", otherwise 129.

Implementation

Mandatory when other than default value allowed.

6.2 ITU‑T Recommendation V.250 [14] dial command D

ITU‑T Recommendation V.250 [14] dial command D lists characters that may be used in a dialling string for making a call or controlling supplementary services in accordance with 3GPP TS 22.030 [19]. Their use is listed in this clause, as well as new dial modifiers are introduced. For an MT supporting AT commands only, it is mandatory to support the control of supplementary services in accordance with 3GPP TS 22.030 [19] through the dial command or through the specific supplementary service commands (+CCFC, +CLCK, etc.), where 3GPP TS 22.030 [19] identifies the supplementary services as mandatory. See also the AT commands for enhanced support of dialling as well as +CMCCS and +CLCCS.

V.250 dialling digits

1 2 3 4 5 6 7 8 9 0 * # + A B C (implementation of these characters is mandatory)

D (implementation of this character is optional, and it is ignored)

V.250 modifier characters

, (implementation of this character is mandatory, but it may be ignored)

T P (implementation of these characters is mandatory, but they are ignored)

! W @ (implementation of these characters is optional, and they are ignored)

V.250 semicolon character

When semicolon character is given after dialling digits (or modifiers), a voice call originated to the given address. TA returns to command state immediately (or after possible +COLP result code; refer clause "Connected line identification presentation +COLP"). Refer Annex G for a detailed example.

Modifier characters

> (refer clause "Direct dialling from phonebooks")

I or i (override the CLIR supplementary service subscription default value for this call; I = invocation (restrict CLI presentation) and i = suppression (allow CLI presentation); refer clause "Calling line identification restriction +CLIR").

G or g (control the CUG supplementary service information for this call; uses index and info values set with command +CCUG or +CECUG; refer clause "Closed user group +CCUG" and clause "Enhanced closed user group +CECUG").

6.3 Direct dialling from phonebooks

MT and SIM/UICC can contain phonebooks which have a phone number and an alphanumeric field for each phonebook entry location. The use of ITU‑T Recommendation V.250 [14] dialling command ensures that direct dialling from MT and SIM/UICC phonebook is possible through ordinary communications software which just gives the phone number field to be filled and then use the D command to originate the call. Available memories may be queried with Select Phonebook Storage test command +CPBS=?, and location range for example with Read Phonebook Entries test command +CPBR=?.

Execute commands

1. D><str>[I][G][;] originate call to phone number which corresponding alphanumeric field is <str> (if possible, all available memories should be searched for the correct entry).

2. D>mem<n>[I][G][;] originate call to phone number in memory mem entry location <n> (available memories may be queried with Select Phonebook Storage test command +CPBS=?; mem could be e.g. ME).

3. D><n>[I][G][;] originate call to phone number in entry location <n> (it is manufacturer specific which memory storage of MT, SIM/UICC in the currently selected card slot and TA is used; command Select Phonebook Memory Storage +CPBS setting is recommended to be used).

Semicolon character shall be added when voice call is originated. CLIR and CUG per call base modifiers may also be present.

Responses

Possible error responses include +CME ERROR: <err> when error is related to MT functionality. Refer clause 9.2 for possible <err> values. Otherwise TA responses can have values defined by ITU‑T Recommendation V.250 [14] and commands Service Reporting Control +CR and Connected Line Identification Presentation +COLP. Detailed error report of an unsuccessful originated call failed in the network error can be obtained with command Extended Error Report +CEER (if implemented).

Defined values

<str>: string type value, which should equal to an alphanumeric field in at least one phonebook entry in the searched memories; used character set should be the one selected with command select TE character set +CSCS.

<n>: integer type memory location should be in the range of locations available in the memory used.

Implementation

Mandatory when direct dialling is implemented. Also phonebook commands implementation is required.

6.4 Call mode +CMOD

Table 12: +CMOD parameter command syntax

Command	Possible response(s)
+CMOD=[<mode>]
+CMOD?	+CMOD: <mode>
+CMOD=?	+CMOD: (list of supported <mode>s)

Description

Set command selects the call mode of further dialling commands (D) or for next answering command (A). Mode can be either single or alternating (in the present document, terms "alternating mode" and "alternating call" refer to all GSM/UMTS bearer and teleservices that incorporate more than one basic service (voice, data, fax) within one call). When single mode is selected the call originating and hangup procedures are similar to procedures specified in ITU‑T Recommendations V.250 [14], T.31 [11] and T.32 [12]. In GSM/UMTS there can be voice followed by data (refer 3GPP TS 22.002 [1]), alternating voice/data (refer 3GPP TS 22.002 [1]) and alternating voice/fax calls (refer 3GPP TS 22.003 [2]). See following clauses for alternating call control methods.

Read command returns the current value of <mode>.

Test command returns values supported as a compound value.

NOTE: +CMOD shall be set to zero after a successfully completed alternating mode call. It shall be set to zero also after a failed answering. The power‑up, factory (&F) and user resets (Z) shall also set the value to zero. This reduces the possibility that alternating mode calls are originated or answered accidentally.

Defined values

<mode>: integer type

0 single mode

1 alternating voice/fax (teleservice 61)

2 alternating voice/data (bearer service 61)

3 voice followed by data (bearer service 81)

all other values below 128 are reserved by the present document.

Implementation

Mandatory when alternating mode calls are implemented in the TA.

6.4A Voice call mode +CVMOD

Table 13: +CVMOD parameter command syntax

Command	Possible response(s)
+CVMOD=[<voice_mode>]
+CVMOD?	+CVMOD: <voice_mode>
+CVMOD=?	+CVMOD: (list of supported <voice_mode>s)

Description

Set command selects the voice call mode for making a Mobile Originated voice call from the UE. The voice call mode can be CS_ONLY, VOIP_ONLY, CS_PREFERRED or VOIP_PREFERRED. Type of VoIP session preferred (e.g. SIP VoIP, IMS VoIP) is manufacturer specific issue.

NOTE 1: If the Call Mode is set to CS_ONLY, then the ATD command will make a call in CS mode.

If the Call Mode is set to VOIP_ONLY, then the ATD command will make a call in VoIP mode.

If the Call Mode is set to CS_PREFERRED, then the ATD command gives preference for CS based voice call.

If the Call Mode is set to VOIP_PREFERRED, then the ATD command gives preference for VoIP based voice call

NOTE 2: As an alternative to the ATD command, the command Dial URI +CDU can be used if supported.

NOTE 3: The preferences are not applicable for the emergency call.

NOTE 4: The preferences are not applicable if operator has set preferences for UE originated calls/sessions, 3GPP TS 24.216 [75] clause 5.6.

Read command returns the current value of <voice_mode>.

Test command returns the values supported by the UE as a compound value.

Defined values

<voice_mode>: integer type. The default value is manufacturer specific.

0 CS_ONLY

1 VOIP_ONLY

2 CS_PREFERRED

3 VOIP_PREFERRED

Implementation

Optional.

6.5 Hangup call +CHUP

Table 13a: +CHUP action command syntax

Command	Possible response(s)
+CHUP
+CHUP=?

Description

Execution command causes the TA to hangup the current call of the MT.

NOTE: The purpose of this command is not to replace the ITU‑T Recommendation V.250 [14] command H, but to give an assured procedure to terminate an alternating mode call. Refer next clause.

Implementation

Mandatory when alternating mode calls implemented in the TA.

6.6 Alternating mode call control method

This clause describes the procedure to handle alternating mode calls with AT commands. Procedures are mandatory when alternating mode calls are implemented in the TA.

NOTE 1: 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 clause "Cellular result codes +CRC" for possible +CRING result code values. Refer Annex F for a detailed example.

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 clause "Cellular result codes +CRC" for possible +CRING result code values. Refer Annex E for a detailed example.

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 2: The transition from fax mode to voice mode is for further study.

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>
+CBST=?	+CBST: (list of supported <speed>s),(list of supported <name>s),(list of supported <ce>s)

Description

Set command selects the bearer service <name> with data rate <speed>, and the connection element <ce> to be used when data calls are originated (refer 3GPP TS 22.002 [1]). Values may also be used during mobile terminated data call setup, especially in case of single numbering scheme calls (refer +CSNS).

Read command returns the current parameter values.

Test command returns values supported as compound values.

Defined values

NOTE: The default values of the subparameters are manufacturer specific since they depend on the purpose of the device and data services provided by it. Not all combinations of these subparameters are supported by GSM/UMTS (refer 3GPP TS 22.002 [1]).

<speed>: integer type

0 autobauding (automatic selection of the speed; this setting is possible in case of 3.1 kHz modem and non-transparent service)

1 300 bps (V.21)

2 1200 bps (V.22)

3 1200/75 bps (V.23)

4 2400 bps (V.22bis)

5 2400 bps (V.26ter)

6 4800 bps (V.32)

7 9600 bps (V.32)

12 9600 bps (V.34)

14 14400 bps (V.34)

15 19200 bps (V.34)

16 28800 bps (V.34)

17 33600 bps (V.34)

34 1200 bps (V.120)

36 2400 bps (V.120)

38 4800 bps (V.120)

39 9600 bps (V.120)

43 14400 bps (V.120)

47 19200 bps (V.120)

48 28800 bps (V.120)

49 38400 bps (V.120)

50 48000 bps (V.120)

51 56000 bps (V.120)

65 300 bps (V.110)

66 1200 bps (V.110)

68 2400 bps (V.110 or X.31 flag stuffing)

70 4800 bps (V.110 or X.31 flag stuffing)

71 9600 bps (V.110 or X.31 flag stuffing)

75 14400 bps (V.110 or X.31 flag stuffing)

79 19200 bps (V.110 or X.31 flag stuffing)

80 28800 bps (V.110 or X.31 flag stuffing)

81 38400 bps (V.110 or X.31 flag stuffing)

82 48000 bps (V.110 or X.31 flag stuffing)

83 56000 bps (V.110 or X.31 flag stuffing; this setting can be used in conjunction with asynchronous non-transparent UDI or RDI service in order to get FTM)

84 64000 bps (X.31 flag stuffing; this setting can be used in conjunction with asynchronous non-transparent UDI service in order to get FTM)

115 56000 bps (bit transparent)

116 64000 bps (bit transparent)

120 32000 bps (PIAFS32k)

121 64000 bps (PIAFS64k)

130 28800 bps (multimedia)

131 32000 bps (multimedia)

132 33600 bps (multimedia)

133 56000 bps (multimedia)

134 64000 bps (multimedia)

all other values below 256 are reserved by the present document.

<name>: integer type

0 data circuit asynchronous (UDI or 3.1 kHz modem)

1 data circuit synchronous (UDI or 3.1 kHz modem)

2 PAD Access (asynchronous) (UDI)

3 Packet Access (synchronous) (UDI)

4 data circuit asynchronous (RDI)

5 data circuit synchronous (RDI)

6 PAD Access (asynchronous) (RDI)

7 Packet Access (synchronous) (RDI)

all other values below 128 are reserved by the present document.

<ce>: integer type

0 transparent

1 non-transparent

2 both, transparent preferred

3 both, non-transparent preferred

Implementation

Mandatory when data calls implemented.

6.8 Radio link protocol +CRLP

Table 15: +CRLP parameter command syntax

Command	Possible response(s)
+CRLP=[<iws>[,<mws>[,<T1>[,<N2>[,<ver>[,<T4>]]]]]]
+CRLP?	+CRLP: <iws>,<mws>,<T1>,<N2>[,<ver1>[,<T4>]] [<CR><LF>+CRLP: <iws>,<mws>,<T1>,<N2>[,<ver2>[,<T4>]] […]]
+CRLP=?	+CRLP: (list of supported <iws>s),(list of supported <mws>s), (list of supported <T1>s),(list of supported <N2>s)[,<ver1> [,(list of supported <T4>s)]] [<CR><LF>+CRLP: (list of supported <iws>s),(list of supported <mws>s),(list of supported <T1>s),(list of supported <N2>s) [,<ver2>[,(list of supported <T4>s)]] […]]

Description

Radio link protocol (RLP) parameters used when non-transparent data calls are originated may be altered with set command. Available command subparameters depend on the RLP versions implemented by the device (e.g. <ver> may not be available if device supports only versions 0 and 1).

NOTE 1: If radio link protocol is not used, but some other error correcting protocol (for transparent data calls), ITU‑T Recommendation V.250 [14] Error Control Selection test command +ES=? may be used to indicate the presence of the protocol.

Read command returns current settings for each supported RLP version <verx>. Only RLP parameters applicable to the corresponding <verx> are returned.

Test command returns values supported as compound values. If MT/TA supports several RLP versions <verx>, the RLP parameter value ranges for each <verx> are returned on a separate line.

Defined values

<ver>, <verx>: RLP version number in integer format; when version indication is not present it shall equal 0

NOTE 2: Versions 0 and 1 share the same parameter set. Read and test commands shall return only one line for this set (where <verx> is not present).

<iws>, <mws>, <T1>, <N2>, <T4>: IWF to MS window size, MS to IWF window size, acknowledgement timer T1, retransmission attempts N2, re-sequencing period T4 in integer format (default values and value ranges depend on RLP version; refer 3GPP TS 24.022 [18]): T1 and T4 are in units of 10 ms.

Implementation

Mandatory when RLP implemented.

6.9 Service reporting control +CR

Table 16: +CR parameter command syntax

Command	Possible response(s)
+CR=[<mode>]
+CR?	+CR: <mode>
+CR=?	+CR: (list of supported <mode>s)

Description

Set command controls whether or not intermediate result code +CR: <serv> is returned from the TA to the TE. If enabled, the intermediate result code is transmitted at the point during connect negotiation at which the TA has determined which speed and quality of service will be used, before any error control or data compression reports are transmitted, and before the intermediate result code CONNECT is transmitted.

NOTE: This command replaces ITU‑T Recommendation V.250 [14] command Modulation Reporting Control +MR, which is not appropriate for use in the GSM/UMTS network. Possible error control (other than radio link protocol) and data compression reporting can be enabled with V.250 commands Error Control Reporting +ER and Data Compression Reporting +DR.

Read command returns the current value of <mode>.

Test command returns values supported as a compound value.

Defined values

<mode>: integer type

0 disables reporting

1 enables reporting

<serv>:

ASYNC asynchronous transparent

SYNC synchronous transparent

REL ASYNC asynchronous non‑transparent

REL SYNC synchronous non‑transparent

GPRS [<L2P>] GPRS

<L2P>: proposes a layer 2 protocol to use between the MT and the TE. It is defined in the Enter GPRS Data Mode (+CGDATA) command.

Implementation

Mandatory when data calls implemented.

6.10 Extended error report +CEER

Table 17: +CEER action command syntax

Command	Possible response(s)
+CEER	+CEER: <report>
+CEER=?

Description

Execution command causes the TA to return one or more lines of information text <report>, determined by the MT manufacturer, which should offer the user of the TA an extended report of the reason for

– the failure in the last unsuccessful call setup (originating or answering) or in‑call modification;

– the last call release;

– the last unsuccessful GPRS attach or unsuccessful PDP context activation;

– the last GPRS detach or PDP context deactivation.

Typically, the text will consist of a single line containing the cause information given by the network in textual format.

Defined values

<report>: the total number of characters, including line terminators, in the information text shall not exceed 2041 characters.

Text shall not contain the sequence 0<CR> or OK<CR>.

Implementation

Optional.

6.11 Cellular result codes +CRC

Table 18: +CRC parameter command syntax

Command	Possible response(s)
+CRC=[<mode>]
+CRC?	+CRC: <mode>
+CRC=?	+CRC: (list of supported <mode>s)

Description

Set command controls whether or not the extended format of incoming call indication or GPRS network request for PDP context activation or notification for VBS/VGCS calls is used. When enabled, an incoming call is indicated to the TE with unsolicited result code +CRING: <type> instead of the normal RING.

Read command returns the current value of <mode>.

Test command returns values supported as a compound value.

NOTE 1: Similar command may be found in TIA IS‑99 [15] and TIA IS‑135 [16].

Defined values

<mode>: integer type

0 disables extended format

1 enables extended format

<type>:

ASYNC [,<priority>[,<subaddr>,<satype>]] asynchronous transparent

SYNC [,<priority>[,<subaddr>,<satype>]] synchronous transparent

REL ASYNC [,<priority>[,<subaddr>,<satype>]] asynchronous non‑transparent

REL SYNC [,<priority>[,<subaddr>,<satype>]] synchronous non‑transparent

FAX [,<priority>[,<subaddr>,<satype>]] facsimile (TS 62)

VOICE [,<priority>[,<subaddr>,<satype>]] normal voice (TS 11) (see NOTE 2)

VOICE/VIDEO [,<ccidx>[,<priority>[,<subaddr>,<satype>]]] voice or video call (see NOTE 2)

VOICE/XXX [,<priority>[,<subaddr>,<satype>]] voice followed by data (BS 81) (XXX is ASYNC, SYNC, REL ASYNC or REL SYNC)

ALT VOICE/XXX [,<priority>[,<subaddr>,<satype>]] alternating voice/data, voice first (BS 61)

ALT XXX/VOICE [,<priority>[,<subaddr>,<satype>]] alternating voice/data, data first (BS 61)

ALT VOICE/FAX [,<priority>[,<subaddr>,<satype>]] alternating voice/fax, voice first (TS 61)

ALT FAX/VOICE [,<priority>[,<subaddr>,<satype>]] alternating voice/fax, fax first (TS 61)

GPRS <PDP_type>, <PDP_addr>[, [<L2P>][,<APN>]] GPRS network request for PDP context activation

VGC <GCA>, <GId>, <ackflag> [,<priority>] voice group call (TS 91)

VBC <GCA>, <GId>, <ackflag> [,<priority>] voice broadcast call (TS 92)

NOTE 2: The <type>=VOICE/VIDEO is used for voice and/or video calls. It is implementation specific whether this type will replace the <type>=VOICE or if both the types <type>=VOICE/VIDEO and <type>=VOICE are supported.

<priority>: indicates the eMLPP priority level of the incoming call by paging, notification or setup message. The priority level values are as defined in eMLPP specification 3GPP TS 22.067 [54].

<subaddr>: string type subaddress of format specified by <satype>.

<satype>: type of subaddress octet in integer format (refer 3GPP TS 24.008 [8] clause 10.5.4.8) or RFC 4715 [122] appendix A.

<ccidx>: integer type. Call identification number, see +CLCCS.

<PDP_type>, <PDP_addr> and <APN>: string types as defined in the Define PDP Context (+CGDCONT) command.

<L2P>: string type proposes a layer 2 protocol to use between the MT and the TE. It is defined in the Enter GPRS Data Mode (+CGDATA) command. If the MT is unable to announce to the TE the network’s request (for example it is in V.250 online data state) the MT shall reject the request. No corresponding unsolicited result code shall be issued when the MT returns to a command state.

<GCA>: string type (consisting of digits only) is a part of the group call reference as specified in 3GPP TS 23.003 [7] and indicates group call area. See the commands +CAJOIN, +CAREJ and +CALCC.

<GId>: string type (consisting of digits only) is a part of the group call reference as specified in 3GPP TS 23.003 [7] and indicates group call identification. See the commands +CAJOIN, +CAREJ and +CALCC.

<ackflag>: integer type proposes that a predefined confirmation procedure is to be used after the call is ended. The value 1 indicates that a predefined confirmation procedure is to be used after the call is ended. The value 0 indicates that no confirmation procedure is required. See the parameter <ack_flag> of command +CALCC.

Implementation

Mandatory when data or fax circuit mode calls are implemented, or for an MT supporting AT commands only and eMLPP or VGCS or VBS is implemented.

6.12 HSCSD device parameters +CHSD

Table 19: +CHSD action command syntax

Command	Possible response(s)
+CHSD	+CHSD: <mclass>,<maxRx>,<maxTx>,<sum>,<codings> +CME ERROR: <err>
+CHSD=?

Description

Execution command returns information about HSCSD features (refer 3GPP TS 22.034 [29]) supported by the MT/TA. Refer clause 9.2 for possible <err> values.

The return information is only applicable in GERAN.

Defined values

<mclass>: integer type; multislot class

<maxRx>: integer type; maximum number of receive timeslots that MT can use

<maxTx>: integer type; maximum number of transmit timeslots that MT can use

<sum>: integer type; total number of receive and transmit timeslots that MT can use at the same time (per TDMA frame). The following applies in a HSCSD call: 1 ≤ (receive slots) + (transmit slots) ≤ <sum>

<codings>: is a sum of integers each representing a supported channel coding (e.g. value 5 indicates that 4,8k and 9,6k channel codings are supported):

1 4,8k full rate data traffic channel

4 9,6k full rate data traffic channel

8 14,4k full rate data traffic channel

16 28,8k full rate data traffic channel (only possible when 14.4k is supported)

32 32,0k full rate data traffic channel (only possible in a two-timeslot configuration)

64 43,2k full rate data traffic channel (only possible when 14.4k is supported)

Implementation

Mandatory when HSCSD implemented.

This command is only applicable to GERAN UEs.

6.13 HSCSD transparent call configuration +CHST

Table 20: +CHST parameter command syntax

Command	Possible response(s)
+CHST=[<wRx>[,<codings>]]
+CHST?	+CHST: <wRx>,<codings>
+CHST=?

Description

Set command controls parameters for transparent HSCSD calls in GERAN. Changing them during a call does not affect the current call.

Read command returns the current values.

NOTE: In UTRAN or E-UTRAN, values set with this command are not needed. The only applicable parameter is <SPEED>, which is set with +CBST command.

Defined values

<wRx>: integer type; wanted amount of receive timeslots. Default value 0 indicates that TA shall calculate a proper value from currently selected fixed network user rate (<speed> subparameter from +CBST command) and <codings>

<codings>: a sum of integers each representing a channel coding that is accepted for transparent HSCSD calls. Default value 0 indicates that all supported codings are accepted (refer +CHSD command for other values)

Implementation

Mandatory when transparent HSCSD implemented.

This command is only applicable to GERAN UEs.

6.14 HSCSD non-transparent call configuration +CHSN

Table 21: +CHSN parameter command syntax

Command	Possible response(s)
+CHSN=[<wAiur>[,<wRx>[,<topRx> [,<codings>]]]]
+CHSN?	+CHSN: <wAiur>,<wRx>,<topRx>,<codings>
+CHSN=?	+CHSN: (list of supported <wAiur>s),(list of supported <wRx>s),(list of supported <topRx>s),(list of supported <codings>s)

Description

Set command controls parameters for originating non-transparent HSCSD calls. Values may also be used during mobile terminated data call setup. In GERAN, changing <topRx> or <codings> value during a call does not affect the current call. In GERAN, changing of <wAiur> or <wRx> affects the current call only if <topRx> was non-zero when call was established.

Read command returns the current values.

Test command returns values supported as compound values.

Defined values

<wAiur>: integer type; wanted air interface user rate. Default value 0 indicates that TA shall calculate a proper value from currently selected fixed network user rate (<speed> subparameter from +CBST command), <codings>, and <wRx> (or <maxRx> from +CHSD command if <wRx>=0). Other values:

1 9600 bps

2 14400 bps

3 19200 bps

4 28800 bps

5 38400 bps

6 43200 bps

7 57600 bps

<wRx>: integer type; wanted amount of receive timeslots. Default value 0 indicates that TA shall calculate a proper value from currently selected <wAiur> and <codings>. This parameter is only applicable to GERAN UEs.

<topRx>: integer type; top value for <wRx> that user is going to request during the next established non-transparent HSCSD call. Default value 0 indicates that user is not going to change <wAiur>/<wRx> during the next call. This parameter is only applicable to GERAN UEs.

<codings>: a sum of integers each representing a channel coding that is accepted for non-transparent HSCSD calls. Default value 0 indicates that all supported codings are accepted (refer +CHSD command for other values). This parameter is only applicable to GERAN UEs.

Implementation

Mandatory when non-transparent HSCSD implemented.

6.15 HSCSD current call parameters +CHSC

Table 22: +CHSC action command syntax

Command	Possible response(s)
+CHSC	+CHSC: <rx>,<tx>,<aiur>,<coding>
+CHSC=?

Description

Execution command returns information about current HSCSD call. If no HSCSD call is active, all parameters returned shall equal zero. If HSCSD call is active in UTRAN, all non-applicable parameters returned shall be equal to zero. (It is manufacturer specific whether non-zero information is returned in case of an active normal single-slot data call.)

Defined values

<rx>: integer type; number of receive timeslots currently in use. This parameter is only applicable to GERAN UEs.

<tx>: integer type; number of transmit timeslots currently in use. This parameter is only applicable to GERAN UEs.

<aiur>: integer type; current air interface user rate (in case of transparent service this equals fixed network user rate) (refer +CHSN command for possible values). For the two-timeslot ECSD bit transparent configuration the following additional values apply:

8 56000 bps

9 64000 bps

<coding>: is a sum of integers each representing the current channel coding (refer +CHSD command for possible values). This parameter is only applicable to GERAN UEs.

Implementation

Optional.

6.16 HSCSD parameters report +CHSR

Table 23: +CHSR parameter command syntax

Command	Possible response(s)
+CHSR=[<mode>]
+CHSR?	+CHSR: <mode>
+CHSR=?	+CHSR: (list of supported <mode>s)

Description

Enabled command returns intermediate result code +CHSR: <type> from the TA to the TE when an HSCSD call is being set up. The result code represents the current (negotiated or renegotiated) HSCSD parameters. If enabled, the intermediate result code is transmitted at the point of the call setup negotiation where the TA has determined what type of an HSCSD connection will be used. Result code transmission is done after possible service (+CR), error control (+ER), and/or compression (+DR) reporting but before possible TE-TA rate (+ILRR) reporting and before the intermediate result code CONNECT is transmitted. The format of the intermediate result code is:

+CHSR: <rx>,<tx>,<aiur>,<coding>

For the value definitions, refer to +CHSN and +CHSC commands. For instance, for a non-transparent HSCSD call, result code ‘+CHSR: 2,2,4,8’ means that the call has two timeslots in both up- and downlink, the air interface user rate is 28800 bps, and the used channel coding TCH/F14.4.

For HSCSD in UTRAN, all non-applicable parameters returned shall be equal to zero.

Read command returns the current value of <mode>.

Test command returns the values supported by the UE as a compound value.

Defined values

<mode>: integer type

0 disables reporting

1 enables reporting

Implementation

Mandatory when HSCSD implemented.

6.17 HSCSD automatic user initiated upgrading +CHSU

Table 24: +CHSU parameter command syntax

Command	Possible response(s)
+CHSU=<mode>
+CHSU?	+CHSU: <mode>
+CHSU=?	+CHSU: (list of supported <mode>s)

Description

Set command controls whether or not automatic user initiated service level upgrading shall be used for non-transparent HSCSD calls. "Automatic" means that, if enabled, the ME/TA shall use the UP bit in the received RLP frames to determine when to initiate user initiated service level upgrading (i.e. when to modify the +CHSN parameters <wAiur> and/or <wRx> for the current call). Refer to 3GPP TS 27.001 [41] for details on the interpretation of the UP bit(s).

Read command returns the current value of <mode>.

Test command returns values supported as a compound value.

NOTE 1: The validity of the UP bit in the RLP frames depends on the result of the RLP negotiations. The UP bit shall only be used if the result of the RLP negotiations were successful with respect to the UP bit.

NOTE 2: This command is only applicable in GERAN.

Defined values

<mode>: integer type

0 disables use of UP bit for upgrading

1 enables use of UP bit for upgrading

Implementation

Optional.

This command is only applicable to GERAN UEs.

6.18 HSCSD non-transparent asymmetry configuration +CHSA

Table 25: +CHSA parameter command syntax

Command	Possible response(s)
+CHSA=<mode>
+CHSA?	+CHSA: <mode>
+CHSA=?	+CHSA: (list of supported <mode>s)

Description

Set command controls the preferred asymmetry bias for non-transparent ECSD calls. Downlink biased asymmetry means that 8-PSK modulation is preferred downlink and GMSK modulation uplink. Uplink based asymmetry means that 8-PSK modulation is preferred uplink and GMSK downlink. Changing of <mode> affects the current call only if <topRx> (refer +CHSN) was non-zero when call was established.

Read command returns the current value of <type>.

Test command returns values supported by the MT/TA as a compound value. The <mode> subparameter range indirectly indicates the UE Type; range (0-1) indicates UE Type A and range (0-2) indicates UE Type B.

NOTE 1: ECSD is also controlled by +CHSD, +CHSN and +CHST.

NOTE 2: This command is only applicable in GERAN.

Defined values

<mode>: integer type

0 No preference

1 Downlink biased asymmetry

2 Uplink biased asymmetry

Implementation

Mandatory when non-transparent ECSD is implemented.

This command is only applicable to GERAN UEs.

6.19 Single numbering scheme +CSNS

Table 26: +CSNS parameter command syntax

Command	Possible response(s)
+CSNS=[<mode>]
+CSNS?	+CSNS: <mode>
+CSNS=?	+CSNS: (list of supported <mode>s)

Description

Set command selects the bearer or teleservice to be used when mobile terminated single numbering scheme call is established. Parameter values set with +CBST command shall be used when <mode> equals to a data service.

Read command returns the current value of <mode>.

Test command returns values supported as a compound value.

Defined values

<mode>: integer type

0 voice

1 alternating voice/fax, voice first (TS 61)

2 fax (TS 62)

3 alternating voice/data, voice first (BS 61)

4 data

5 alternating voice/fax, fax first (TS 61)

6 alternating voice/data, data first (BS 61)

7 voice followed by data (BS 81)

Implementation

Optional.

6.20 Voice hangup control +CVHU

Table 27: +CVHU parameter command syntax

Command	Possible response(s)
+CVHU=[<mode>]
+CVHU?	+CVHU: <mode>
+CVHU=?	+CVHU: (list of supported <mode>s)

Description

Set command selects whether ATH or "drop DTR" shall cause a voice connection to be disconnected or not. By voice connection is also meant alternating mode calls that are currently in voice mode. (See clause 6.6).

Read command returns the current value of <mode>.

Test command returns values supported as a compound value.

NOTE: When <mode>=2, this command must be seen in conjunction with the ITU‑T Recommendation V.250 [14] command &D. Else &D shall be ignored.

Defined values

<mode>: integer type

0 "Drop DTR" ignored but OK response given. ATH disconnects.

1 "Drop DTR" and ATH ignored but OK response given.

2 "Drop DTR" behaviour according to &D setting. ATH disconnects.

Implementation

Optional

6.21 CCITT V.120 [36] rate adaption protocol +CV120

Table 28: +CV120 parameter command syntax

Command	Possible response(s)
+CV120=[<rah>[,<mfm>[,<mode>[,<llineg>[,<assign>[,<negtype>]]]]]]
+CV120?	+CV120: <rah>,<mfm>,<mode>,<llineg>,<assign>,<negtype>
+CV120=?	+CV120: (list of supported <rah>s),(list of supported <mfm>s),(list of supported <mode>s),(list of supported <llineg>s),(list of supported <assign>s),(list of supported <negtype>s)

Description

Set command sets the values of the V.120 protocol parameters (defined in CCITT Recommendation V.120 [36]) that are carried in the GSM BC and/or LLC information elements.

Read command returns current settings for the V.120 parameters.

Test command returns values supported as compound values.

Defined values

<rah>: integer type

0 rate adaption header not included

1 rate adaption header included (mandatory for protocol sensitive modes).

<mfm>: integer type

0 multiple frame establishment not supported, only UI frames allowed

1 multiple frame establishment supported, both I and UI frames allowed.

<mode>: integer type

0 bit transparent mode of operation

1 protocol sensitive mode of operation.

<llineg>: integer type

0 no negotiation, LLI = 256 only

1 negotiation allowed.

NOTE: <negtype> indicates the connection over which the negotiation is performed.

<assign>: integer type

0 message originator is "default assignee"

1 message originator is "assignor only".

<negtype>: integer type

0 negotiation is done using logical link zero

1 negotiation is done with USER INFORMATION messages on a temporary signalling connection.

All possible modes of V.120 operation are not supported. However, in order to accommodate possible future additions, the complete set of parameters is included in the command.

The permitted values are: 1, 1 or 0, 1, 0, 0, 0.

A recommended set of default values is: 1, 1, 1, 0, 0, 0.

Implementation

Mandatory, if the MT supports V.120 interworking.

6.22 Settings date format +CSDF

Table 29: +CSDF parameter command syntax

Command	Possible response(s)
+CSDF=[[<mode>][,<auxmode>]]	+CME ERROR: <err>
+CSDF?	+CSDF: <mode>[,<auxmode>] +CME ERROR: <err>
+CSDF=?	+CSDF: (list of supported <mode>s) [,(list of supported <auxmode>s)] +CME ERROR: <err>

Description

This command sets the date format via MMI of the date information presented to the user, which is specified by use of the <mode> parameter. The <mode> affects the date format on the phone display and doesn’t affect the date format of the AT command serial interface. The command also sets the date format of the TE-TA interface, which is specified by use of the <auxmode> parameter (e.g. the <auxmode> affects the <time> of +CCLK and +CALA). If the parameter is omitted ("+CSDF=","+CSDF=<mode>","+CSDF=,<auxmode>"), then this sets the default value. Refer clause 9.2 for possible <err> values.

Read command returns the current settings.

Test command returns values supported as compound values.

Defined values

<mode>: integer type

NOTE 1: It is manufacturer specific which modes that are supported.

1 DD-MMM-YYYY

NOTE 2: Presentation of MMM is language dependent.

2 DD-MM-YY

3 MM/DD/YY

4 DD/MM/YY

5 DD.MM.YY

6 YYMMDD

7 YY-MM-DD

8-255 Manufacturer specific

<auxmode>: integer type

1 yy/MM/dd

2 yyyy/MM/dd

all other values are reserved by the present document.

NOTE 3: The <time> format of +CCLK and +CALA "yy/MM/dd,hh:mm:ss±zz" when <auxmode>=1 and it is "yyyy/MM/dd,hh:mm:ss±zz" when <auxmode>=2. If the MT does not support time zone information then the three last characters may be omitted (see +CCLK command).

Implementation

Optional

6.23 Silence command +CSIL

Table 30: +CSIL parameter command syntax

Command	Possible response(s)
+CSIL=[<mode>]	+CME ERROR: <err>
+CSIL?	+CSIL: <mode> +CME ERROR: <err>
+CSIL=?	+CSIL: (list of supported <mode>s) +CME ERROR: <err>

Description

Set command enables/disables the silent mode. When the phone is in silent mode, all sounds from MT are suppressed except voice. Refer clause 9.2 for possible <err> values.

Read command reads the current setting.

Test command lists the supported modes as a compound value.

Defined values

<mode>: integer type. The default value is manufacturer specific.

0 Silent mode off

1 Silent mode on

Implementation

Optional

6.24 Settings time format +CSTF

Table 31: +CSTF parameter command syntax

Command	Possible response(s)
+CSTF=[<mode>]	+CME ERROR: <err>
+CSTF?	+CSTF: <mode> +CME ERROR: <err>
+CSTF=?	+CSTF: (list of supported <mode>s) +CME ERROR: <err>

Description

Set command sets the time format of the time information presented to the user. Refer clause 9.2 for possible <err> values.

Read command reads the current setting.

Test command reads the supported <modes>s as a compound value.

Defined values

<mode>: integer type. The default value is manufacturer specific.

1 HH:MM (24 hour clock)

2 HH:MM a.m./p.m.

3-7 Manufacturer specific

Implementation

Optional

6.25 ITU‑T Recommendation V.250 [14] call control commands

Table 32: V.250 call control commands

Command	Clause	Impl.	Used in the present document
D[<dial_string>][;]	6.3.1	mand.	originates a call
T	6.3.2	mand.	ignored (select tone dialling)
P	6.3.3	mand.	ignored (select pulse dialling)
A	6.3.5	mand.	answer a call
H[<value>]	6.3.6	mand.	hang‑up a single mode call; for alternate mode call refer clause "Hangup call +CHUP" (only value equal to zero needed)
O[<value>]	6.3.7	mand.	returns TA to online data state from online command mode (only value equal to zero needed)
S0=[<value>]	6.3.8	mand.	sets the number of call indications (rings) before automatically answering the call; value equalling zero disables automatic answering and is the default
S6=[<value>]	6.3.9	mand.	ignored (pause before blind dialling)
S7=[<value>]	6.3.10	mand.	sets number of seconds to wait for completion of call answering or originating procedure before giving up and disconnecting
S8=[<value>]	6.3.11	mand.	sets number of seconds to wait when comma dial modifier encountered in dial string of D command (default is 2 seconds)
S10=[<value>]	6.3.12	mand.	sets number of tenths of seconds to wait before disconnecting after TA has indicated the absence of received line signal
L[<value>]	6.3.13	mand.	ignored (monitor speaker loudness)
M[<value>]	6.3.14	mand.	ignored (monitor speaker mode)

Implementation of commands marked as mandatory is mandatory only if call control functionality is supported.

6.26 ITU‑T Recommendation V.250 [14] data compression commands

Table 33: V.250 data compression commands

Command	Clause	Impl.	Used in the present document
+DS=[<dir>[,<neg>[,<P1>[,<P2>]]]]	6.6.1	mand. when V.42bis	controls ITU‑T Recommendation V.42bis data compression functions; for subparameter defaults refer 3GPP TS 24.022 [18]
+DR=[<value>]	6.6.2	mand. when V.42bis	determines whether the use of V.42bis is informed using intermediate result code +DR: <type> before going online data state after call answering or originating

6.27 Initiate eCall +CECALL

Table 6.27-1: +CECALL parameter command syntax

Command	Possible response
+CECALL=<type_of_eCall>[,<format>,<msd_data_length>,<msd_data>]
+CECALL?	+CECALL: [<type_of_eCall>[,<format>,<msd_data_length>,<msd_data>[,<format>,<msd_data>,[…]]]]
+CECALL=?	+CECALL: (list of supported <type_of_eCall>s)[,(list of supported <format>s)]

Description

Set command is used to trigger an eCall to the network or to provide an updated MSD to the network during an ongoing eCall. Based on the configuration selected, it can be used to either trigger a test call, a reconfiguration call, a manually initiated eCall or an automatically initiated eCall. The parameters <format>, <msd_data_length> and <msd_data> are included if the MSD is provided by the application. If the parameters are not included, the MSD is provided to the network by the MT.

Read command returns the <type_of_eCall> that is currently in progress, if any. The MT may also return the <format>s and the <msd_data>s of the eCall as provided to the network. The parameters of the response to the read command will be cleared when the eCall in progress is terminated.

Test command returns the supported values as compound values.

Defined values

<type_of_eCall>: integer type. Indicates the type of eCall.

0 test call

1 reconfiguration call eCall

2 manually initiated eCall

3 automatically initated eCall

<format>: integer type. Indicates the format of the provided eCall MSD.

1 binary format

<msd_data_length>: integer type. Indicates the number of octets of the <msd_data> information element.

<msd_data>: string type. Minimum set of data, see CEN EN 15722:2015 [157]. The type of string is in the format specified by <format>. This parameter shall not be subject to conventional character conversion as per +CSCS.

Implementation

Optional.

6.28 eCall Notification +CECN

Table 6.28-1: +CECN parameter command syntax

Command	Possible response
+CECN=[<n>]
+CECN?	+CECN: <n>
+CECN=?	+CECN: (list of supported <n>s)

Description

Set command is used to control the presentation of an unsolicited result code +CECN: <data_type> when <n>=1 and the network requests an updated MSD during an eCall. As a result of the unsolicited result code +CECN, the AT-command +CECALL can be used to provide an updated MSD for the eCall.

NOTE: The parameter <data_type>=0 is used to inform that the updated MSD will be provided to the network by the MT.

Read command returns the status of result code presentation <n>.

Test command returns the supported values as a compound value.

Defined values

<n>: integer type. Enables or disables reporting of unsolicited result code +CECN.

0 disable presentation of the unsolicited result code

1 enable presentation of the unsolicited result code

<data_type>: integer type. Indicates the type of additional data for the eCall.

0 updated MSD for the eCall is provided to the network by the MT

1 request for updated MSD

Implementation

Optional.

6.29 Informative examples

The alternating mode call handling (voice and fax, or voice and data) and the data call setup commands are defined such that the dialling command of ITU‑T Recommendation V.250 [14] (D) still always originates a call. The purpose is to support all current TE applications using the dialling command as default. Fax calls are controlled following the rules of ITU‑T Recommendation T.31 [11] and ITU‑T Recommendation T.32 [12] standards.

An example where a voice call is originated:

ATD+1 812 555673I; (type of address defaults to 145, CLI presentation is restricted for this call)

OK (call setup was successful)

An example where a voice call is attempted from a phonebook:

ATD>"Doe Joe"G; (enable CUG control for this call)

+CME ERROR: 22 (entry "Doe Joe" is not found)

Also supplementary services can be controlled using dial command according to 3GPP TS 22.030 [19]. An example of call forwarding on no reply for telephony with the adjustment of the no reply condition timer on 25 seconds:

ATD**61*+1812555673*11*25#

OK (modification was successful)

Two new commands are created for controlling the alternating mode calls. First one, Call Mode (+CMOD), selects between single and alternating mode. Because this is a crucial command, it is defined that the value is set back to zero (single mode) after every successfully originated alternating mode call. Also on power‑up and factory or user resets, the value is set to zero. The second new command, Hangup Call (+CHUP), is not a replacement of ITU‑T Recommendation V.250 [14] command H, but a command which reliably disconnects the call in GSM/UMTS network. This is defined because the H command is used to switch from fax or data mode to voice mode.

The setting of GSM/UMTS bearer service (data circuit duplex asynchronous and synchronous, PAD access circuit asynchronous, or data packet duplex synchronous), is done with Select Bearer Service Type (+CBST). It chooses one of the four mentioned bearer services, the data rate of the service (or actually the modulation when modem IWFs are used), and enables or disables RLP. Command Radio Link Protocol (+CRLP) is used to set the RLP parameters in the radio path.

Service Reporting Control command (+CR) is defined similarly as the reporting of modulation, V.18, error control, and data compression which are ITU‑T Recommendation V.250 [14] features used to show information about the type of the established connection before the CONNECT intermediate result code. +CR command has one subparameter which specifies whether the intermediate result code +CR: <serv> is returned or not. The result code is typically returned before any ITU‑T Recommendation V.250 [14] reporting result codes. An example of setting up an asynchronous 9600 bit/s modem connection with service reporting:

AT+CBST=7,0,1 (asynchronous modem 9600 bit/s and RLP)

OK

AT+CR=1 (enable reporting)

OK

ATD1234567890

+CR: REL ASYNC

CONNECT 9600

As GSM/UMTS network offers more information about the reason of the failure in call originating and answering than normal PSTN, it is useful to add an extra command to return this information to the TE. This information should not be returned always after unsuccessful call originating or answering, because many TE applications look for just the regular NO CARRIER, BUSY, NO ANSWER and CONNECT messages. Action command Extended Error Report (+CEER) does not have any subparameters, and it returns the cause of the latest call setup failure. This information can be the textual presentation of the GSM/UMTS network failure code (refer 3GPP TS 24.008 [8] Annex H), or some other information defined by the TA manufacturer.