ITU T.61

T.61 is an ITU-T recommendation for a Teletex character set. T.61 predated Unicode, and was the primary character set in ASN.1 used in early versions of X.500 and X.509 for encoding strings containing characters used in Western European languages. While T.61 continues to be supported in modern versions of X.500 and X.509, it has been deprecated in favor of Unicode.

While ASN.1 does see wide use and the T.61 character set is used on some standards using ASN.1 (for example in RSA_Security's PKCS #9), the T.61 standard itself was withdrawn by the ITU-T and is no longer available.