type for binary data

Hello everyone,
I cannot find a suitable type for a chunk of binary data (about 1400
bytes) in PostgreSQL 65.3. database which I access via ODBC (in MySQL
I'm usinng BLOB type and in MS Access LONGBINARY type). I'm using
SQL_C_BINARY binding for reading the data and
SQL_C_BINARY/SQL_LONGVARBINARY binding for updating it. Status after
updating corresponds to the size of the data (1400) stored, but I read
it immediately after it says that only 5 bytes read (I hope I'm
interpreting the value of status well). I tried to change
SQL_LONGVARBINARY to SQL_LONGVARCHAR but still I do not get back what I
store.
What type should I use, please? Or is it something with ODBC? I'm using
unixODBC-1.8.3 (a patch that recently appeared on this list concerning
BLOBs and ODBC has been applied int this release and I believe the
Postgres driver is pretty up-to-date).
Thank you a lot.

Regards,
Ales Pour