[30.09.2009 17:38:27] [info] Server Name :Firebird
[30.09.2009 17:38:27] [info] Server Version :2.5.0.25593
[30.09.2009 17:38:27] [info] Client Name :Firebird SQL Server
[30.09.2009 17:38:27] [info] Client Version :2.5.0.25593
[30.09.2009 17:38:27] [info] Database ODS :11.2
[30.09.2009 17:38:27] [info] Database Dialect:3

----------
1. Connection charset: NONE

create table TEST_NONE
(
 VARCHAR_1 VARCHAR(1) CHARACTER SET NONE
);

insert into test_none values (ascii_char(1));

2. Connection charset: CP943C

select * from TEST_NONE;

ERROR: arithmetic exception, numeric overflow, or string truncation. string right truncation

Same problem with GB18030 connection charset

----
With WIN1251/BIG_5 connection charsets - no any problem