US-ASCII is 7-bit ASCII, an ANSI/ISO standard set that only supports English and defines 128 characters. US-ASCII is enabled by default.
TD-ASCII is a proprietary mix of Latin-1 (ISO-8859-1) and Latin-9 (ISO-8859-15) that supports English and western European languages. TD-ASCII is a Teradata Latin byte-compatible encoding and defines 256 characters and differs by 8% (20 characters) when compared to Latin-1.
TD-ASCII import to Teradata Latin does not return any errors. TD-ASCII import is a pass-through translation (no repertoire verification). This is even the case for the import of the substitute character (0x1A). Note that this causes downstream errors (6706) when the 0x1A is converted to Unicode (U+FFFD).
On import, US-ASCII differs from TD-ASCII in these ways:
- The US-ASCII 0x80 to 0xFF (high bit on) non-characters result in a new 6734 error returned for these 128 characters. The error returns for both the Unicode and Latin destination server character sets.
- The KanjiSJIS destination server character set does not allow the US-ASCII import and returns the existing 6701 error.