SMS: Supported letters, symbols, etc.?

Archived from groups: alt.cellular.siemens (More info?)

David Meisel wrote:

> I'm working on a program which enables the user to indirectly
> increase the amount of letters and symbols one is allowed to
> use when sending or receiving a message via Short Message
> Service (SMS). Does anyone know which letters, numbers,
> symbols (etc.) are supported? (A list or something similar
> would be perfect.)

A standard SMS contains a maximum of 140 bytes. The SMS default
alphabet uses 7-bit characters, allowing 160 characters to be
packed into those 140 bytes.

Alternatively, either standard 8-bit ASCII or 16-bit UCS2
characters can be used (by setting the appropriate bits in the
message header). Using one of these character sets (especially
UCS2) opens up the possibilities considerably (assuming they
can be displayed on a receiving device), but restricts the
maximum size of a single SMS to 140 or 70 characters
respectively.

The 7-bit default alphabet is specified in GSM 03.38, which you
can download free from www.etsi.org. Search for "03.38" when
you get to the download details area, and pick a recent version
from the list. GSM 03.38 also contains the packing algorithm
for coding 7-bit text into PDU (Protocol Data Unit) strings.

Note that a few 7-bit alphabet symbols (like the Euro currency
symbol) are from an extension table. Each such character
requires 2 character positions within an SMS.

John