Cinterion
®
ENS22-E AT Command Set
1.6 Supported character sets
ENS22-E_ATC_V01.000
19/02/11
Page 16 of 189
1.6
Supported character sets
Cinterion
®
ENS22-E supports two character sets:
GSM 7 bit
, also referred to as GSM alphabet or SMS
alphabet (3GPP TS 23.038
) and
UCS216 bit
(ISO-10646
). See
for information about
selecting the character set. Character tables can be found below.
Explanation of terms
• Escape Character
There are two types of escape sequences which lead to an alternative interpretation on subsequent charac-
ters by the UE:
- AT command interface
Escape sequences starting with character value 0x5C are used for the UE's non-UCS2 input and output.
- GSM 7 bit default alphabet
If the escape sequence used within a text starts with character value 0x1B in the GSM 7 bit default alpha-
bet, which represents the extension character and needs to be correctly interpreted by the TE, both for
character input and output. To the
Cinterion
®
ENS22-E, an escape sequence appears like any other
byte received
or sent.
• TE Character Set
The character set currently used by the Customer Application is selected with
. It is recommended
to select UCS2 setting.
• Data Coding Scheme (DCS)
DCS is part of a short message and is saved on the SIM.
• International Reference Alphabet (IRA)
The International Reference Alphabet is equivalent to ASCII (American Standard Code for Information Inter-
change) and ISO 646, i.e. it defines a 7-bit coded character set. The mapping can be obtained from the char-
acter set tables below (UCS2 values 0x0000 to 0x007F).
When you enter characters that are not valid characters of the supported alphabets the behavior is undefined.
If GSM alphabet is selected, all characters sent over the serial line (between TE and UE) must be in the range
from 0 to 127 (7 bit range).
Note: If the UE is configured for GSM alphabet, but the Customer Application (TE) uses ASCII, bear in mind that
some characters have different code values, such as the following:
• "@" character with GSM alphabet value 0 is not displayable by an ASCII terminal program, e.g. Microsoft©
Hyperterminal®.
• "@" character with GSM alphabet value 0 will terminate any C string! This is because value 0 is defined as C
string end tag. Therefore, the GSM Null character will cause problems on application level when using 'C'-
functions, e.g. "strlen()". Using an escape sequence as shown in the table below solves the problem. By the
way, this may be the reason why even network providers sometimes replace '@' with "@=*" in their SIM appli-
cation.
• Some other characters of the GSM alphabet may be misinterpreted by an ASCII terminal program. For exam-
ple, GSM "ö" (as in "Börse") is assumed to be "|" in ASCII, thus resulting in "B|rse". This is because in both
alphabets there are different characters assigned to value 7C (hexadecimal).
If the TE sends characters differently coded or undefined in ASCII or GSM (e.g. Ä, Ö, Ü) it is possible to use
escape sequences. The UE's input parser translates the escape sequence to the corresponding GSM character
value.
Note:
The UE also uses escape sequences for its non-UCS2 output: Quotation mark (") and the escape character itself
(\, respectively Ö in GSM alphabet) are converted, as well as all characters with a value below 32 (hexadecimal
0x20).
Hence, the input parser of the Customer Application needs to be able to translate escape sequences back to the
corresponding character of the currently used alphabet.
Unsupported characters are shown as a space (hexadecimal 0x20).