Folks
Having a small problem with my 9300 when sending some accentuated SMS (for instance in French)
Depending on the usage of some non ASCII128 characters in my messages, the software automatically switches to UNICODE, hence reducing my message size to 80 signs (16 bits encoding�).
Is there any way to force ASCII encoding ?
If not, what are the �legal� ASCII chars (it seems that it�s not strict 7 bit ASCII) ?
Any info / reference material appreciated !
Alex
An SMS message of 7-bit characters is encoded in 140 octets (8-bits/octet or 1 byte) giving the 160 character long messages.
In most current phones, if you enter characters outside the GSM default alphabet, the encoding is automatically switched to UCS2 (Unicode based 16-bit / 2-octet / 2-byte encoding) allowing 70 unicode characters in the 140 octet space.
There is no way for a user to control the encoding used. It is assumed to be the default alphabet, unless you type a character that's not included in that set (which is a way - in a way 😊 - to "force" things in either direction).
Of course, modern phones, if you write longer messages, they are automatically split and sent as several messages (and then combined at the receiving side), so the the user doesn't really see it going out or coming in as multiple messages (except on older phones).
The GSM default alphabet is a 7-bit character set defined in the ETSI GSM Phase 2+ Technical Specification 03.38 available from http://pda.etsi.org/pda/queryform.asp
The complete document title is "Digital cellular telecommunications system (Phase 2+); Alphabets and language-specific information (GSM 03.38)"
The document reference number is: TS/SMG-040338QR2
The GSM default alphabet includes at least these "accented" characters: �����������������������
The complete table is in the 03.38 spec (section 6.21. Default alphabet), so check there, if you want to be absolutely sure.
There is also an 8-bit alphabet, but it is used for service messages or something like that.
Thanks for this most detailed response.
😊
Not much to add, except that when using "�" in a french SMS, my serie 40 phone was somehow able to transmit the message without reverting to UNICODE whereas my serie 80 now does.
Not a major issue, though
Regards
Alex