Re: Simple string conversion from UCS2 to ISO8859-1

On 2/25/25 2:35 AM, pozz wrote:

Il 24/02/2025 21:13, Lawrence D'Oliveiro ha scritto:

On Mon, 24 Feb 2025 16:57:24 +0100, pozz wrote:
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Il 22/02/2025 14:18, David Brown ha scritto:

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My understanding here is that the OP is getting the UCS-2 encoded
string in from a modem, almost certainly on a serial line.  The UCS-2
encoded data is itself a binary sequence of 16-bit code units, and the
modem firmware is sending those as four hex digits.
>

Exactly. This is the reply to AT+CMGR command that is standardized in
3GPP TS 27.005.

>
Anything that is specifying the use of UCS-2 encoding automatically dates
itself to about the early-to-mid 1990s.

 Sincereley I don't know why and when, but the LTE modem I'm using (Simcom A7672E) replies to AT+CMGR in two different format:
 - what is described as GSM 7-bit alphabet (but it's really UTF-8 when non ASCII chas are present)
 - UCS2
 Of course, in the header, it specifies the <dcs> (data coding scheme) so the receiver on the UART can interpret correctly all the data.
 

Are you sure it is UCS2 and not UTF-16?
Can it not handle characters not in the BMP?
The difference between UCS2 and UTF-16 is that UCS2 is the character set that predates the surrogate-pairs added to extend it. It is very much the equivalent relationship of ASCII to UTF-8.