Re: Simple string conversion from UCS2 to ISO8859-1

On 26/02/2025 04:37, Keith Thompson wrote:

Lawrence D'Oliveiro <ldo@nz.invalid> writes:

On Tue, 25 Feb 2025 15:53:23 +0100, pozz wrote:
>

Sincerely I don't know, the standard says UCS2

>
Remembered that the specs are online
<https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1514>.
They don’t actually say what “data coding schemes” are allowed; the
only mention of UCS-2 is
>
     if <dcs> indicates that 8-bit or UCS2 data coding scheme is used,
     or <fo> indicates that 3GPP TS 23.040 [3]
     TP-User-Data-Header-Indication is set: ME/TA converts each 8-bit
     octet into two IRA character long hexadecimal number (e.g. octet
     with integer value 42 is presented to TE as two characters 2A (IRA
     50 and 65))
>
So it doesn’t say that UTF-16 is or isn’t allowed.

 It doesn't say that EBCDIC or UTF-7 is or isn't allowed.
 

There are two specifications at work here.  One is the 3G standards about coding schemes used for SMS data, and the other is the common AT command set.  The later is, I think, mostly a de-facto standard - modem manufacturers have tried to keep a common subset (along with their own device-specific commands).  3G may allow for 8-bit encoding sets without specifying them in detail, but the modem commands are more specific - the ones used by the OP are strictly UCS-2.
(It is a /long/ time since I have read details of these things, so I might be misremembering.)