Siemens MC55 AT manual

•If writing fails due to timeout, then

AT^SM20 <CmgwMode>=1 causes "+CMS ERROR: Unknown error" to be returned;

AT^SM20 <CmgwMode>=0 causes "+CMS ERROR: timer expired" to be returned.

•Note that some providers do not recognize an @ symbol used in a short message. A widely used alternative is typing "*" as defined in GSM 03.40 (GPP TS 23.40).

•For baudrates lower than 19200 it is recommended to use the line termination character only (refer to ATS3= <n>, default <CR>) before entering the text or PDU. Use of the line termination character followed by the response formating character (see ATS4= <n>, default <LF>) may cause problems.

•SMS-COMMANDs and SMS-STATUS-REPORTs cannot be stored in text mode.

•All characters entered behind the ">" prompt will be recognized as GSM characters. For example, "Back- space" (ASCII character 8) does not delete a character, but will be inserted into the short message as an addi- tional physical character. As a result, the character you wanted to delete still appears in the text, plus the GSM code equivalent of the Backspace key.

•Message Length in Text Mode

The maximum length of a short message depends on the used coding scheme: It is 160 characters if the 7 bit GSM coding scheme is used, and 140 characters according to the 8 bit GSM coding scheme.

In case UCS2 character set selected it is highly recommended to set Data Coding Scheme (<dcs> of AT+CSMP) to 16-bit data, otherwise the length of sms user data is restricted to 88 octets. Even better for mes- sages with UCS2 character set is the PDU Mode.

•The length of 8-bit data coded short messages has to be greater than 0.

MC55_ATC_V04.00	Page 345 of 475	3/17/06
Confidential / Released