Hayes command set - Wikipedia

Hayes Command Set
From: https://en.wikipedia.org/wiki/Hayes_AT_command_set


Description Syntactical Defns Modem Init Example Sess Compatibility Autobaud Basic Cmd Set	Modem S Reg Dfns V.250 GSM Examples Of GSM Cmds Voice Cmds See Also Notes And References External Links


Description
Description
The following text lists part of the Hayes command set, also called the AT
 commands: "AT" meaning 'attention'. Each command string is prefixed with
 "AT", and a number of discrete commands can be concatenated after the
 "AT".

The Hayes command set can subdivide into four groups:

basic command set – A capital character followed by a digit. For
 example, M1.
extended command set – An "&" (ampersand) and a capital character
 followed by a digit. This extends the basic command set. For example, &M1.
 Note that M1 is different from &M1.
proprietary command set – Usually starting either with a backslash
 (“\”) or with a percent sign (“%”); these commands vary widely
 among modem manufacturers.
register commands – Sr=n where r is the number of the register to be
 changed, and n is the new value that is assigned. A register represents a
 specific physical location in memory. Modems have small amounts of memory
 on board. The fourth set of commands serves for entering values into a
 particular register (memory location). For example, S7=60 instructs the
 modem to "Set register #7 to the value 60". Registers usually control
 aspects of the modem operation (e.g. transmission strength, modulation
 parameters) and are usually specific to a particular model.

Although the command-set syntax defines most commands by a letter-number
 combination (L0, L1 etc.), the use of a zero is optional. In this example,
 "L0" equates to a plain "L". Keep this in mind when reading the table
 below.

When in data mode, an escape sequence can return the modem to command mode.
 The normal escape sequence is three plus signs ("+++"), and to
 disambiguate it from possible real data, a guard timer is used: it must be
 preceded by a pause, not have any pauses between the plus signs, and be
 followed by a pause; by default, a "pause" is one second and "no pause" is
 anything less.



Syntactical definitions
The following syntactical definitions apply:[7]

<CR> Carriage return character, is the command line and result code
 terminator character, which value, in decimal ASCII between 0 and 255, is
 specified in register S3. The default value is 13.
<LF> Linefeed character, is the character recognised as line feed character.
 Its value, in decimal ASCII between 0 and 255, is specified in register
 S4. The default value is 10. The line feed character is output after the
 carriage return character if verbose result codes are used (V1 option is
 used); otherwise, if numeric format result codes are used (V0 option is
 used), it will not appear in the result codes.
<...> Name enclosed in angle brackets is a syntactical element. They do not
 appear in the command line.
[...] Optional subparameter of a command or an optional part of AT
 information response is enclosed in square brackets. Brackets themselves
 do not appear in the command line. When the subparameter is not given in
 AT commands which have a Read command, the new value equals its previous
 value. In AT commands which do not store the values of any of their
 subparameters, and so have not a Read command, which are called action
 type commands, the action should be done on the basis of the recommended
 default setting of the subparameter.



Modem initialization
A string can contain many Hayes commands placed together, so as to
 optimally prepare the modem to dial out or answer, e.g. AT&F&D2&C1S0=0X4.
 Most modem software supported a user supplied initialization string, which
 was typically a long concatenated AT command which was sent to the modem
 upon launch.[8] The V.250 specification requires all DCEs to accept a body
 (after "AT") of at least 40 characters of concatenated commands.[9]



Example session
The following represents two computers, computer A and computer B, both
 with modems attached, and the user controlling the modems with
 terminal-emulator software. Terminal-emulator software typically allows
 the user to send Hayes commands directly to the modem, and to see the
 responses. In this example, the user of computer A makes the modem dial
 the phone number of modem B at phone number (212) 555-0100 (long
 distance). After every command and response, there is a carriage return
 sent to complete the command.


Modem A Modem B Comment
ATDT12125550100 User at modem A issues a dial command: AT-Get the
 modem's ATtention; D-Dial; T-Touch-Tone; 12125550100-Call this number
RING Modem A begins dialing. Modem B's phone-line rings, and the modem
 reports the fact.
ATA Computer at modem B issues answer command.
CONNECT CONNECT The modems connect, and both modems report "connect". (In
 practice, most modems report more information after the word CONNECT —
 specifying the speed of the connection.) Also, at this time, both modems
 will raise the DCD, or Data Carrier Detect signal, on the serial port.
abcdef abcdef When the modems are connected, any characters typed at
 either side will appear on the other side. The person at computer A starts
 typing. The characters pass through the modem and appear on computer B's
 screen. (User A may not see his own typed characters — depending on the
 terminal software's local echo setting).
+++ The person at computer B issues the modem escape command.
 (Alternately, and more commonly, the computer B could drop the DTR, or
 Data Terminal Ready signal, to achieve a hangup, without needing to use
 +++ or ATH.)
OK The modem acknowledges it.
ATH The person at computer B issues a hang up command.
NO CARRIER OK Both modems report that the connection has ended. Modem B
 responds "OK" as the expected result of the command; modem A says NO
 CARRIER to report that the remote side interrupted the connection. The
 modems on both sides drop their DCD signals as well.




Compatibility
While the original Hayes command set represented a huge leap forward in
 modem-based communications, with time many problems set in, almost none of
 them due to Hayes per se:

Due to the lack of a written standard, other modem manufacturers just
 copied the external visible commands and (roughly) the basic actions. This
 led to a wide variety of subtle differences in how modems changed from
 state to state, and how they handled error conditions, hangups, and
 timeouts.
Each manufacturer tended to add new commands to handle emerging needs,
 often incompatible with other modems. For example, setting up hardware or
 software handshaking often required many different commands for different
 modems. This undermined the handy universality of the basic Hayes command
 set.
Many Hayes compatible modems had serious quirks that made them effectively
 incompatible. For example, many modems required a pause of several seconds
 after receiving the "AT Z" reset command. Some modems required spaces
 between commands, while others did not. Some would unhelpfully change
 baud-rate of their own volition, which would leave the computer with no
 clue how to handle the incoming data.

As a result of all this, eventually many communications programs had to
 give up any sense of being able to talk to all "Hayes-compatible" modems,
 and instead the programs had to try to determine the modem type from its
 responses, or provide the user with some option whereby they could enter
 whatever special commands it took to coerce their particular modem into
 acting properly.



Autobaud
The Hayes command set facilitated automatic baud rate detection as "A" and
 "T" happen to have bit patterns that are very regular; "A" is "100 0001"
 and so has a 1 bit at the start and end and "T" is "101 0100" which has a
 pattern with (nearly) every other bit set.[10] Since the RS-232 interface
 transmits least significant bit first, the according line pattern with
 8-N-1 (eight data bits, no parity bit, one stop bit) is
 01000001010001010101 (start and stop bits italicized) which is used as
 syncword.



The basic Hayes command set
The following commands are understood by virtually all modems supporting an
 AT command set, whether old or new.


Command Description Comments
A0 or A Answer incoming call  
A/ Repeat last command Do not preface with AT, do not follow with
 carriage return. Enter usually aborts.
D Dial Dial the following number and then handshake
P – Pulse Dial
T – Touch Tone Dial
W – Wait for the second dial tone
R – Reverse to answer-mode after dialing
@ - Wait for up to 30 seconds for one or more ringbacks
, - Pause for the time specified in register S8 (usually 2 seconds)
; – Remain in command mode after dialing.
! – Flash switch-hook (Hang up for a half second, as in transferring a call.)
L – Dial last number
E0 or E No Echo Will not echo commands to the computer
E1 Echo Will echo commands to the computer (so one can see what one
 types if the computer software does not support echo)
H0 or H Hook Status On hook. Hangs up the phone, ending any call in
 progress.
H1 Hook status Off hook. Picks up the phone line (typically you'll hear
 a dialtone)
I0 to I9 Inquiry, Information, or Interrogation This command returns
 information about the model, such as its firmware or brand name. Each
 number (0 to 9, and sometimes 10 and above) returns one line of
 modem-specific information, or the word ERROR if the line is not defined.
 Today, Windows uses this for Plug-and-play detection of specific modem
 types.
L0 or Ln (n=1 to 3) Speaker Loudness. Supported only by some modems with
 speakers. Modems lacking speakers, or with physical volume controls, or
 ones whose sound output is piped through the sound card will not support
 this command. 0 turns off speaker, 1 to 3 are for increasing volumes.
M0 or M Speaker Mute, completely silent during dialing M3 is also
 common, but different on many brands
M1 Speaker on until remote carrier detected (user will hear dialing and
 the modem handshake, but once a full connection is established the speaker
 is muted)
M2 Speaker always on (data sounds are heard after CONNECT)
O Return Online Returns the modem back to the normal connected state
 after being interrupted by the "+++" escape code.
Q0 or Q Quiet Mode Off – Displays result codes, user sees command
 responses (e.g. OK)
Q1 Quiet Mode On – Result codes are suppressed, user does not see
 responses.
Sn Select current register
Note that Sn, ? and =r are actually three separate commands, and can be
 given in separate AT commands.
Select register n as the current register
Sn? Select register n as the current register, and query its value.
 Using ? on its own will query whichever register was most recently
 selected.
Sn=r Select register n as the current register, and store r in it. Using
 =r on its own will store into whichever register was most recently
 selected.
V0 or V Verbose Numeric result codes
V1 English result codes (e.g. CONNECT, BUSY, NO CARRIER etc.)
X0 or X Smartmodem Hayes Smartmodem 300 compatible result codes
X1 Usually adds connection speed to basic result codes (e.g. CONNECT
 1200)
X2 Usually adds dial tone detection (preventing blind dial, and
 sometimes preventing ATO)
X3 Usually adds busy signal detection.
X4 Usually adds both busy signal and dial tone detection
Z0 or Z Reset Reset modem to stored configuration, and usually also
 physically power-cycles the modem (during which it is unresponsive). Z0',
 Z1 etc. are for multiple stored profiles. &F is similar in that it returns
 to factory default settings on modems without NVRAM (non volatile memory),
 but it does not reset the modem


Note:
a command string is terminated with a CR (\r) character

Although not part of the command set, a tilde character ~ is commonly used
 in modem command sequences. The ~ causes many applications to pause
 sending the command stream to the device (usually for half a second), e.g.
 after a Reset. The ~ is not sent to the modem.[11]



Modem S register definitions


Register Description Range Default value
S0 Number of rings before Auto-Answer 0–255 (0 = never) 0
S1 Ring Counter 0–255 rings 0
S2 Escape character 0–255, ASCII decimal 43 ("+")
S3 Carriage Return Character 0–127, ASCII decimal 13 (Carriage
 Return)
S4 Line Feed Character 0–127, ASCII decimal 10 (Line Feed)
S5 Backspace Character 0–32, ASCII decimal 8 (Backspace)
S6 Wait Time before Blind Dialing 2–255 seconds 2
S7 Wait for Carrier after Dial 1–255 seconds 50
S8 Pause Time for Comma (Dial Delay) 0–255 seconds 2
S9 Carrier Detect Response Time 1–255 tenths of a seconds 6 (0.6
 second)
S10 Delay between Loss of Carrier and Hang-Up 1–255 tenths of a
 second 14 (1.4 seconds)
S11 DTMF Tone Duration 50–255 milliseconds 95 milliseconds
S12 Escape Code Guard Time 0–255 fiftieths of a second 50 (1 second)
S18 Test Timer 0–255 seconds 0 seconds
S25 Delay to DTR 0–255 (seconds if synchronous mode, hundredths of a
 second in all other modes) 5
S26 RTS to CTS Delay Interval 0–255 hundredths of a second 1
 hundredth of a second
S30 Inactivity Disconnect Timer 0–255 tens of seconds 0 (disable)
S37 Desired Telco Line Speed 
0–10
Command options:
    0 Attempt auto mode connection
    1 Attempt to connect at 300 bit/s
    2 Attempt to connect at 300 bit/s
    3 Attempt to connect at 300 bit/s
    5 Attempt to connect at 1200 bit/s
    6 Attempt to connect at 2400 bit/s
    7 Attempt to connect in V.23 75/1200 mode.
    8 Attempt to connect at 9600 bit/s
    9 Attempt to connect at 12000 bit/s
    10 Attempt to connect at 14400 bit/s
0
S38 Delay before Force Disconnect 0–255 seconds 20 seconds




V.250
The ITU-T established a standard in its V-Series Recommendations, V.25 ter,
 in 1995 in an attempt to establish a standard for the command set again.
 It was renamed V.250 in 1998 with an annex that was not concerning the
 Hayes command set renamed as V.251. A V.250 compliant modem implements the
 A, D, E, H, I, L, M, N, O, P, Q, T, V, X, Z, &C, &D, and &F commands in
 the way specified by the standard. It must also implement S registers and
 must use registers S0, S3, S4, S5, S6, S7, S8, and S10 for the purposes
 given in the standard. It also must implement any command beginning with
 the plus sign, "+" followed by any letter A to Z, only in accordance with
 ITU recommendations. Modem manufacturers are free to implement other
 commands and S-registers as they see fit, and may add options to standard
 commands.

V.250 – Defined leading character sequences 


Leading characters Includes commands related to
+A Call control (network Addressing) issues, common, PSTN, ISDN, ITU-T
 Rec. X.25, switched digital
+C Digital Cellular extensions
+D Data Compression, ITU-T Rec. V.42 bis
+E Error Control, ITU-T Rec. V.42
+F Facsimile, ITU-T Rec. T.30, etc.
+G Generic issues such as identity and capabilities
+I DTE-DCE Interface issues, ITU-T Rec. V.24, etc.
+M Modulation, ITU-T Rec. V.32 bis, etc.
+P PCM DCE commands, ITU-T Rec. V.92
+S Switched or Simultaneous Data Types
+T Test issues
+V Voice extensions
+W Wireless extensions




GSM
The ETSI GSM 07.07 (3GPP TS 27.007) specifies AT style commands for
 controlling a GSM phone or modem. The ETSI GSM 07.05 (3GPP TS 27.005)
 specifies AT style commands for managing the Short Message Service (SMS)
 feature of GSM.



Examples of GSM commands:[12][13]


Command Description
AT+CPIN=1234 Enter PIN code
AT+CPWD="SC","old","new" Change PIN code from 'old' to 'new'
AT+CLCK="SC",0,"1234" Remove PIN code
AT&V Status
ATI Status (Manufacturer, Model, Revision, IMEI, capabilities)
AT+COPS=? List available networks 0-Unknown/2-Current/3-Forbidden,
 Longname, Shortname, Numerical-ID, "AcT"
AT+CSQ Get signal strength. Answer: +CSQ: , 
ATD*99# Dial access point
AT+CGDCONT=1,"IP","access.point.name" Defines PDP context[12]


GSM/3G modems typically support the ETSI GSM 07.07/3GPP TS 27.007 AT
 command set extensions, although how many commands are implemented varies.

Most USB modem vendors, such as Huawei, Sierra Wireless, Option, have also
 defined proprietary extensions for radio mode selection (GSM/3G
 preference) or similar. Some recent high speed modems provide a virtual
 Ethernet interface instead of using a Point-to-Point Protocol (PPP) for
 the data connection because of performance reasons (PPP connection is only
 used between the computer and the modem, not over network). The set-up
 requires vendor-specific AT command extensions. Sometimes the
 specifications for these extensions are openly available, other times the
 vendor requires an NDA for access to these.[14]



Voice command set
Main article: Voice modem command set
Modems with voice or answering-machine capabilities support a superset of
 these commands to enable digital audio playback and recording.



See also

Access Point Name (APN)
Command and Data modes (modem)
ITU-T Recommendations:
	
H.324 (video)
T.31 (fax)




Notes and references

^ a b Victoria Shannon (January 7, 1999). "The Rise and Fall of the Modem King".
 The New York Times. "with a partner"
^ Georgi Dalakov. "The Modem of Dennis Hayes and Dale Heatherington".
 Retrieved January 8, 2015.
^ "Hayes compatible". Computerworld. March 30, 1987. p. 61.
^ "How to Set Up a Hayes Compatible Modem". June 17, 2018.
^ Max, Schau (27 September 1998). "1+2=3, +++ATH0=Old school DoS". Bugtraq
 mailing list. Retrieved 8 December 2012.
^ Frank Durda IV, "The AT Command Set Reference – History" Archived
 2008-04-15 at the Wayback Machine, 1993
^ AT Commands Reference Guide [dead link]
^ "Initialization Strings: Why, What & Where". Archived from the original on
 2009-03-10. Retrieved 2008-04-09.
^ "5.2.1 Command line general format" (PDF), V.250 : Serial asynchronous
 automatic dialling and control (05/99, 07/03), ITU-T/Telecommunication
 Standardization Bureau
^ "Serial Interfaces". PICList. Retrieved 2016-05-15.
^ "More Modem Commands". Chebucto Community Net. Retrieved 2016-09-12.
^ a b "Developers guidelines June 2010 AT commands for Sony Ericsson phones".
 Archived from the original on 2011-09-29. 090505
 developer.sonyericsson.com
^ "UC864-E Software User Guide" (PDF). Archived from the original (PDF) on
 2011-07-14. 090505 m2m-platforms.com
^ "Dan Williams' blog – That's when I reach for my revolver…".




External links

List of AT commands: Basic (Hayes), Extended, Proprietary
Hayes AT Command Reference Manual
A list of Hayes AT commands
3gpp.org, 3GPP AT command set for User Equipment
Modem initialisation string Archived 2009-03-10 at the Wayback Machine
Extended Hayes AT command parameters for SMS (dead)
Determining your Class of Fax / Modem
Openmoko: AT Commands
Cell modem commands
ITU Standard V.250
AT Commands Reference Guide from Telit (dead)

Modem A	Modem B	Comment
ATDT12125550100		User at modem A issues a dial command: AT-Get the modem's ATtention; D-Dial; T-Touch-Tone; 12125550100-Call this number
	RING	Modem A begins dialing. Modem B's phone-line rings, and the modem reports the fact.
	ATA	Computer at modem B issues answer command.
CONNECT	CONNECT	The modems connect, and both modems report "connect". (In practice, most modems report more information after the word CONNECT — specifying the speed of the connection.) Also, at this time, both modems will raise the DCD, or Data Carrier Detect signal, on the serial port.
abcdef	abcdef	When the modems are connected, any characters typed at either side will appear on the other side. The person at computer A starts typing. The characters pass through the modem and appear on computer B's screen. (User A may not see his own typed characters — depending on the terminal software's local echo setting).
	+++	The person at computer B issues the modem escape command. (Alternately, and more commonly, the computer B could drop the DTR, or Data Terminal Ready signal, to achieve a hangup, without needing to use +++ or ATH.)
	OK	The modem acknowledges it.
	ATH	The person at computer B issues a hang up command.
NO CARRIER	OK	Both modems report that the connection has ended. Modem B responds "OK" as the expected result of the command; modem A says NO CARRIER to report that the remote side interrupted the connection. The modems on both sides drop their DCD signals as well.

Command	Description	Comments
A0 or A	Answer incoming call
A/	Repeat last command	Do not preface with AT, do not follow with carriage return. Enter usually aborts.
D	Dial	Dial the following number and then handshake P – Pulse Dial T – Touch Tone Dial W – Wait for the second dial tone R – Reverse to answer-mode after dialing @ - Wait for up to 30 seconds for one or more ringbacks , - Pause for the time specified in register S8 (usually 2 seconds) ; – Remain in command mode after dialing. ! – Flash switch-hook (Hang up for a half second, as in transferring a call.) L – Dial last number
E0 or E	No Echo	Will not echo commands to the computer
E1	Echo	Will echo commands to the computer (so one can see what one types if the computer software does not support echo)
H0 or H	Hook Status	On hook. Hangs up the phone, ending any call in progress.
H1	Hook status	Off hook. Picks up the phone line (typically you'll hear a dialtone)
I0 to I9	Inquiry, Information, or Interrogation	This command returns information about the model, such as its firmware or brand name. Each number (0 to 9, and sometimes 10 and above) returns one line of modem-specific information, or the word ERROR if the line is not defined. Today, Windows uses this for Plug-and-play detection of specific modem types.
L0 or Ln (n=1 to 3)	Speaker Loudness. Supported only by some modems with speakers. Modems lacking speakers, or with physical volume controls, or ones whose sound output is piped through the sound card will not support this command.	0 turns off speaker, 1 to 3 are for increasing volumes.
M0 or M	Speaker Mute, completely silent during dialing	M3 is also common, but different on many brands
M1		Speaker on until remote carrier detected (user will hear dialing and the modem handshake, but once a full connection is established the speaker is muted)
M2		Speaker always on (data sounds are heard after CONNECT)
O	Return Online	Returns the modem back to the normal connected state after being interrupted by the "+++" escape code.
Q0 or Q	Quiet Mode	Off – Displays result codes, user sees command responses (e.g. OK)
Q1	Quiet Mode	On – Result codes are suppressed, user does not see responses.
Sn	Select current register Note that Sn, ? and =r are actually three separate commands, and can be given in separate AT commands.	Select register n as the current register
Sn?		Select register n as the current register, and query its value. Using ? on its own will query whichever register was most recently selected.
Sn=r		Select register n as the current register, and store r in it. Using =r on its own will store into whichever register was most recently selected.
V0 or V	Verbose	Numeric result codes
V1		English result codes (e.g. CONNECT, BUSY, NO CARRIER etc.)
X0 or X	Smartmodem	Hayes Smartmodem 300 compatible result codes
X1		Usually adds connection speed to basic result codes (e.g. CONNECT 1200)
X2		Usually adds dial tone detection (preventing blind dial, and sometimes preventing ATO)
X3		Usually adds busy signal detection.
X4		Usually adds both busy signal and dial tone detection
Z0 or Z	Reset	Reset modem to stored configuration, and usually also physically power-cycles the modem (during which it is unresponsive). Z0', Z1 etc. are for multiple stored profiles. &F is similar in that it returns to factory default settings on modems without NVRAM (non volatile memory), but it does not reset the modem

Register	Description	Range	Default value
S0	Number of rings before Auto-Answer	0–255 (0 = never)	0
S1	Ring Counter	0–255 rings	0
S2	Escape character	0–255, ASCII decimal	43 ("+")
S3	Carriage Return Character	0–127, ASCII decimal	13 (Carriage Return)
S4	Line Feed Character	0–127, ASCII decimal	10 (Line Feed)
S5	Backspace Character	0–32, ASCII decimal	8 (Backspace)
S6	Wait Time before Blind Dialing	2–255 seconds	2
S7	Wait for Carrier after Dial	1–255 seconds	50
S8	Pause Time for Comma (Dial Delay)	0–255 seconds	2
S9	Carrier Detect Response Time	1–255 tenths of a seconds	6 (0.6 second)
S10	Delay between Loss of Carrier and Hang-Up	1–255 tenths of a second	14 (1.4 seconds)
S11	DTMF Tone Duration	50–255 milliseconds	95 milliseconds
S12	Escape Code Guard Time	0–255 fiftieths of a second	50 (1 second)
S18	Test Timer	0–255 seconds	0 seconds
S25	Delay to DTR	0–255 (seconds if synchronous mode, hundredths of a second in all other modes)	5
S26	RTS to CTS Delay Interval	0–255 hundredths of a second	1 hundredth of a second
S30	Inactivity Disconnect Timer	0–255 tens of seconds	0 (disable)
S37	Desired Telco Line Speed	0–10 Command options: 0 Attempt auto mode connection 1 Attempt to connect at 300 bit/s 2 Attempt to connect at 300 bit/s 3 Attempt to connect at 300 bit/s 5 Attempt to connect at 1200 bit/s 6 Attempt to connect at 2400 bit/s 7 Attempt to connect in V.23 75/1200 mode. 8 Attempt to connect at 9600 bit/s 9 Attempt to connect at 12000 bit/s 10 Attempt to connect at 14400 bit/s	0
S38	Delay before Force Disconnect	0–255 seconds	20 seconds

Leading characters	Includes commands related to
+A	Call control (network Addressing) issues, common, PSTN, ISDN, ITU-T Rec. X.25, switched digital
+C	Digital Cellular extensions
+D	Data Compression, ITU-T Rec. V.42 bis
+E	Error Control, ITU-T Rec. V.42
+F	Facsimile, ITU-T Rec. T.30, etc.
+G	Generic issues such as identity and capabilities
+I	DTE-DCE Interface issues, ITU-T Rec. V.24, etc.
+M	Modulation, ITU-T Rec. V.32 bis, etc.
+P	PCM DCE commands, ITU-T Rec. V.92
+S	Switched or Simultaneous Data Types
+T	Test issues
+V	Voice extensions
+W	Wireless extensions

Command	Description
AT+CPIN=1234	Enter PIN code
AT+CPWD="SC","old","new"	Change PIN code from 'old' to 'new'
AT+CLCK="SC",0,"1234"	Remove PIN code
AT&V	Status
ATI	Status (Manufacturer, Model, Revision, IMEI, capabilities)
AT+COPS=?	List available networks 0-Unknown/2-Current/3-Forbidden, Longname, Shortname, Numerical-ID, "AcT"
AT+CSQ	Get signal strength. Answer: +CSQ: ,
ATD*99#	Dial access point
AT+CGDCONT=1,"IP","access.point.name"	Defines PDP context[12]