To use the SMS you have to declare the number of the Short Message Service Centre (SMSC) in the Mobile Station (MS), provided that the MS supports Short Message Service-Mobile Orginated (SMS-MO).
The M20 Terminal supports SMS-MO.
At the M20 Terminal you enter the SMSC-number with the AT+Celular command:
at+csca = ?<SMSC-number>?
If the receiver of the SMS possesses a Telstra SIM card, the AT command has to be entered in the following way:
at+csca = "+61418706700"
With the command
you can question the current SMSC-number.Ask your network operator for the right SMSC-number !!
|MS: Mobile Station|
|SME: Short Message Entity|
|SMSC: Short Message Service Centre|
|MMI: Man Machine Interface|
|PDUs: Protocol Data Units|
|SM-AL: Short Message Aplication Layer|
|SM-TL: Short Message Transport Layer|
|SM-RL: Short Message Relay Layer|
|SM-LL: Short Message Link Layer|
The MMI is based on the command set of AT+Cellular, and could be realized by means of a terminal (for example Win-Terminal, HyperTerminal, etc) or the display of a handy.
The SM-TL provides a service to the Short Message Application Layer. This service enables the SM-AL to transfer short messages to its peer entity, receive short messages from its peer entity and receive reports about earlier requests for short messages to be transferred. The SM-TL communicates with its peer entity with six several PDUs (Protocol Data Units):
The M20 Terminal supports the SMS-DELIVER and SMS-SUBMIT PDUs as described in the following sections.
! Notice: Any unused bits will be set to zero by the sending entity and will be ignored by the receiving entity !
|SCA||Service Centre Address ? information element||Telephone number of the Service Centre|
|Protocol Data Unit Type|
|Sucessive number (0..255) of all SMS-SUBMIT Frames set by the M20|
|OA||Originator Address||Address of the originating SME|
|DA||Destination Address||Address of the destination SME|
|PID||Protocol Identifier||Parameter showing the SMSC how to process the SM (as FAX, Voice etc)|
|DCS||Data Coding Scheme||Parameter identifying the coding scheme within the User Data (UD)|
|SCTS||Service Centre Time Stamp||Parameter identifying time when the SMSC received the message|
|VP||Validity Period||Parameter identifying the time from where the message is no longer valid in the SMSC|
|UDL||User Data Length||Parameter indicating the length of the UD-field|
|UD||User Data||Data of the SM|
|RP||Reply Path||Parameter indicating that Reply Path exists|
|UDHI||User Data Header Indicator||Parameter indicating that the UD field contains a header|
|SRI||Status Report Indication||Parameter indicating if the SME has requested a status report|
|SRR||Status Report Request||Parameter indicating if the MS has requested a status report|
|VPF||Validity Period Format||Parameter indicating whether or not the VP field is present|
|MMS||More Messages to Send||Parameter indicating whether or not there are more messages to send|
|MTI||Message Type Indicator
00 means SMS-DELIVER
|Parameter describing the message type
01 means SMS-SUBMIT
The octet ?len? contains the number of octets required for the number of the Service Centre plus the 1 byte ?type of number?.
type of number:
81H: the following number is national 91H: the following number international
(For further information see GSM 04.08 chapter 10.5.4.6)octet:
One octet includes two BCD-digit Fields. If the called party BCD number contains an odd number of digits, the last digit shall be filled with an end mark coded as �FH�.Example:
if you have the SC-number +61418706700 you have to type:07911614786007F0
! Notice: If the �len� field is set to Zero the M20 Terminal takes the default value of the Service Centre address set by the AT+CSCA command!
! Notice: you have to write the PDU-type in Hex-Format, a possible example is �11H� !
RP: 0 Reply Path parameter is not set in this PDU 1 Reply Path parameter is set in this PDU UDHI: 0 The UD field contains only the short message 1 The beginning of the UD field contains a header in addition of the short message SRI: (is only set by the SMSC) 0 A status report will not be returned to the SME 1 A status report will be returned to the SME SRR: 0 A status report is not requested 1 A status report is requested VPF: bit4 bit3 0 0 VP field is not present 0 1 Reserved 1 0 VP field present an integer represented (relative) 1 1 VP field present an semi-octet represented (absolute) any reserved values may be rejected by the SMSC MMS: (is only set by the SMSC) 0 More messages are waiting for the MS in the SMSC 1 No more messages are waiting for the MS in the SMSC RD: 0 Instruct the SMSC to accept an SMS-SUBMIT for an short message still held in the SMSC which has the same MR and DA as a previously submitted short message from the same OA. 1 Instruct the SMSC to reject an SMS-SUBMIT for a short message still held in the SMSC which has the same MR and DA as a previously submitted short message from the same OA. MTI: bit1 bit0 Message type 0 0 SMS-DELIVER (SMSC ==> MS) 0 0 SMS-DELIVER REPORT (MS ==> SMSC, is generated automatically by the M20, after receiving a SMS-DELIVER) 0 1 SMS-SUBMIT (MS ==> SMSC) 0 1 SMS-SUBMIT REPORT (SMSC ==> MS) 1 0 SMS-STATUS REPORT (SMSC ==> MS) 1 0 SMS-COMMAND (MS ==> SMSC) 1 1 Reserved
(The fat-marked lines represent the features supported by the M20 Terminal)
! Notice: not every PDU Type is supported by the Service Centre !
The MR field gives an integer (0..255) representation of a reference number of the SMS-SUBMIT submitted to the SMSC by the MS.
! Notice: at the M20 Terminal the MR is generated automatically, -anyway you have to generate it - a possible entry is for example �00H� !
OA and DA have the same format explained in the following lines:len:
The octet �len� contains the number of BCD digitstype of number:
81H: the following number is national
91H: the following number international
(For further information see GSM 04.08 chapter 10.5.4.6)BCD-digits:
The BCD-digit Field contains the BCD-number of the Destination e.g. the Originator.
If the called party BCD number contains an odd number of digits, the last digit shall be filled with an end mark coded as �FH�.Example:
if you have the national number 1234567 you have to type:
The PID is the information element by which the Transport Layer either refers to the higher layer protocol being used, or indicates interworking with a certain type of telematic device.
Here are some examples of PID codings:
00H: The PDU has to be treat as a short message 01H: The PDU has to be treat as a telex 02H: The PDU has to be treat as group3 telefax 03H: The PDU has to be treat as group4 telefax
(For further information see GSM 03.40 chapter 18.104.22.168)
! Notice: it is not guaranteed that the SMSC supports every PID codings!
The DCS field indicates the data coding scheme of the UD (User Data) field, and may indicate a message class. The octet is used according to a coding group which is indicated in bits 7..4. The octet is then coded as follows:
Unspecified message handling at the MS
0000 Default alphabet (7 bit data coding in the User Data)
|0001-1110||Reserved coding groups|
Data Coding/message class
bit 3 is reserved, set 0
bit 2 (message coding)
0 Default alphabet (7 bit data coding in the User Data)
1 8-bit data coding in the User Data
bit 1 bit 0 (message class)
0 0 Class0 immediate display
0 1 Class1 ME (Mobile Equipment)- specific
1 0 Class2 SIM specific message
1 1 Class3 TE (Terminate Equipment)- specific
Default alphabet indicates that the UD (User Data) is coded from the 7-bit alphabet given in appendix A. When this alphabet is used, eight characters of the message are packed in seven octets, and the message can consist of up to 160 characters (instead of 140 characters in 8-bit data coding)
In 8-bit data coding, you can relate to the INTEL ASCII-HEX table.
In Class 0 (immediate display) the short message is written directly in the display, as the M20 Terminal has no display the Class 0 message can be realised only in a roundabout way.
In Class 1 to Class 3 the short message is stored in the several equipments ME, SIM-card and TE.
In time the Class 2 is supported, if you choose Class 1 or Class 3 the short message is treated the same way as a Class 2 message.
! Note: It is recommended to use the Class2 message, or the coding group �0000 bin� !
The SCTS is the information element by which the SMSC informs the recipient MS about the time of arrival of the short message at the Transport Layer entity of the SMSC. The time value is included in every SMS-DELIVER being delivered to the SMSC, and represents the local time in the following way:
The Time Zone indicates the difference, expressed in quarters of an hour, between the local time and GMT (Greenwich Main Time).
The Validity-Period is the information element which gives an MS submitting an SMS-SUBMIT to the SMSC the possibility to include a specific time period value in the short message. The Validity Period parameter value indicates the time period for which the short message is valid, i.e. for how long the SMSC shall guarantee its existence in the SMSC memory before delivery to the recipient has been carried out.
The VP field is given in either integer or semi-octet representation. In the first case, the VP comprises 1 octet, giving the length of the validity period, counted from when the SMS-SUBMIT is received by the SMSC. In the second case, the VP comprises 7 octets, giving the absolute time of the vality period termination. In the first case, the representation of time is as follows:
|VP Value||Validity period value|
|0-143||(VP + 1) x 5 minutes (i.e 5 minutes intervals up to 12 hours)|
|144-167||12 hours + ((VP-143) x 30 minutes)|
|168-196||(VP-166) x 1 day|
|197-255||(VP - 192) x 1 week|
In the second case, the representation of time is identical to the representation or the SCTS (Service Centre Time Stamp).
The case of representation is set in the VPF (Validity Period Format) in the PDU-type.
The UDL field gives an integer representation of the number of characters within the User Data field to follow.
Here are two examples of how to send a short message with AT+Cellular (refer to Appendix B for more details on how to send the SMS messages):
First enter PIN-number and the Service Centre Address:
at+cpin="XXXX" enter the PIN-number OK at+csca="+61418706700" enter the Service-Centre-Address (Telstra) OK
== 1st Example == at+cmgs=18 enter �send message�, 18 is the actual length of the PDU message in octet > 0011000A81409079344400000105E8329BFD06 type the PDU (SMS-SUBMIT) and finish with �ctrl Z� the thin-typed characters are the Destination Address e.g. the own tel.-number(0409974344) the Service Centre address is the same as set via at+csca command +CMGS: 0 OK at+cpms? are messages stored on the SIM-Card? +CPMS: "SM" , 1 , 7 , "SM" , 1 , 7 on this SIM-Card is 1 message stored OK you can store at most 7 messages at+cmgr=1 read stored message in location 1 +CMGR: 0,,24 07911614786007F0040B911604994743F400009930139100406B05E8329BFD06 This is a PDU (SMS- OK -DELIVER) sent by the Service Centre
== 2nd Example == at+cmgw=18 write message in the memory of the SIM-card > 07911614786007F011000781409079344400F6AA0568656C6C6F type the PDU (SMS-SUBMIT) and finish with �ctrl Z� the thin-typed characters are the Destination Address e.g. the own tel.-number (0409974344). The Service Centre Address is �+61418706700� +CMGW: 2 OK at+cmgr=2 read stored message in location 2 +CMGR: 2,,18 07911614786007F011000A81407008090500F6010568656C6C6F this is the PDU stored in location 2 OK at+cmss=2 send the message stored in location 2 +CMSS: 3 OK at+cmss=2,�0407485455�,129 send the message stored in location 2 to the national (129 = 81H) destination address �0407485455� at+cmss=2,�+61419877302�,145 send the message stored in location 2 to the international (145 = 91H) destination address �+61419877302� at+cpms? are messages stored on the SIM-Card? +CPMS: "SM" , 3 , 7 , "SM" , 3 , 7 on this SIM-Card are 3 message stored OK you can store at most 7 messages at+cmgr=3 read stored message in location 3 +CMGR: 0,,24 07911614786007F0040B911604994743F400009930139100406B05E8329BFD06 This is a PDU (SMS- OK -DELIVER) sent by the
This document describes the process of sending SMS messages between a mobile phone and the M20 Terminal. The mobile phone referred to in this document is the Ericsson GH688. However, SMS message can be sent out or received in a similar fashion using other mobile phones.
The following items are needed.
Insert a SIM card into the mobile phone and turn the phone on. The phone is now ready for sending and receiving SMS. Note that you need the phone number for SMS messages.
Connect the M20 Terminal to a PC as shown in Figure 1. Then do the following:
Table 1: Communications Settings
|Baud Rate||19200 bps|
|Connector||COM1 or COM2|
AT+CMGF=0[ENTER] Set the M20 Terminal to PDU mode AT+CMGF=1[ENTER] Set the M20 Terminal to text mode
AT+CSCA=�+61418706700�[ENTER] Enter the SMS Centre AddressNote that the Service Centre Address only needs to be entered once for all SMS.
Figure 1: M20 Terminal Set Up
A mobile phone that is capable of sending and receiving SMS messages can be used to send a SMS message to the M20 Terminal. Note that the SIM card for the mobile phone must be on the same network as the SIM card in the M20 Terminal for SMS messages. eg. both SIM cards must be Telstra, or Optus.
To send a SMS message to the M20 Terminal, select [Send Messages] from the [Mail] menu and then select [New]. Enter your text and when you have finished press the �YES� button. You will then need to enter the destination number for the SMS message. This is the phone number on the SIM card used by the M20 Terminal.
In PDU mode, to send a message like the word �hello�, initially, you have to convert it to a PDU format message. Refer to section 3 (Parameter description) for details on how to construct the PDU message. Note that the actual length of the PDU string (without the Service Centre Address) must be specified for all SMS. Follow the steps below for sending the SMS message.
Step 1. Enter the actual length of the SMS message in octets
Step 2. Enter the SMS message in PDU format and terminate it with �CTRL Z�
The M20 Terminal should return
+CMGS: 12 OK
where 12 is the message reference MR, which is different for every SMS message sent.
In text mode, to send a message, eg. �hello�, follow the three steps below.
Step 1: Set the M20 Terminal for text SMS using
Step 2: Enter the destination phone number in international format
Step 3: Enter the text message and terminate it with �CTRL Z�
The M20 Terminal should return
+CMGS: 1 OK
where 1 is the message reference MR, which is different for every SMS message sent.
When there is a new SMS message arrived, the phone will beep and the SMS message indicator will appear on the phone screen.
To read the SMS message, select [Read Messages] from the [Mail] menu using the left or right arrow button and the new message is usually shown first. Press the �YES� button to read the message. The message can be deleted using the �CLR� button.
In PDU mode, when the M20 Terminal receives a SMS message, the following message will appear on the PC screen.
+CMTI: �SM�, 1
where 1 is the memory location in which the message can be read from.
To read a SMS message from a particular location in memory (eg. location 1) use the AT+CGMR command as follow.
The M20 Terminal should return the PDU message as follow.
+CMGR: 0,,24 07911614786007F0040B911604994743F400009930139100406B05E8329BFD06 OK
where 0 is the status code indicating a received and already read message, 24 is the hexadecimal number indicating the length of the message.
Like PDU mode, when the M20 Terminal receives a SMS message, the following message will appear on the PC screen.
+CMTI: �SM�, 1
where 1 is the memory location in which the message can be read from.
To read the SMS message use the AT+CGMR command as follow.
The M20 Terminal should return the text message as follow.
+CMGR: �REC READ�,�+61407809050�,�98/12/01,20:16:11+44� hello OK
The SMS message can be deleted from memory (eg. location 1) using the AT+CMGD command as follow. Note that there is no AT command to delete all the SMS messages at once.
The M20 Terminal should return OK.