What encoding does MS Windows telnet use by default?

I have a telnet server that allows user to specify encoding for communication. Server will then use that encoding for communication, given it's supported.

I tried following encodings which all produced garbage from unicode characters on the target:

• CP-1252
• UTF-8
• Latin1

The server also allows me to list all encoding along with ěščřžýáíé characters to test which one will work. This is the output in Windows Telnet:

UTF-8: ─Ť┼í─Ź┼Ö┼ż├Ż├í├ş├ę ISO-8859-1: ?????řßÝÚ latin1: ?????řßÝÚ CP819: ?????řßÝÚ IBM819: ?????řßÝÚ iso-ir-100: ?????řßÝÚ csISOLatin1: ?????řßÝÚ ISO-8859-15: ?Ę??ŞřßÝÚ latin9: ?Ę??ŞřßÝÚ ☺Y☺~☺řßÝÚ a☺ ☺Y☺~řßÝÚE: ☺☺a☺ ☺Y☺~☺řßÝÚ☺ ☺Y☺~☺řßÝÚa☺ ☺Y☺~řßÝÚE: ☺a☺ ☺Y☺~☺řßÝÚ System: Big5-HKSCS: n????? h q m Big5: ????????? Big5-ETen: ????????? CP950: ????????? windows-949: ????????? CP949: ????????? EUC-KR: ????????? Shift_JIS: ????????? SJIS: ????????? MS_Kanji: ????????? ISO-2022-JP: ????????? JIS7: ????????? EUC-JP: ????????? GB2312: ????? GBK: CP936: MS936: windows-936: GB18030: 0 8 0 0 0 0 0 6 0 5 hp-roman8: ? ??? roman8: ? ??? csHPRoman8: ? ??? TIS-620: ????????? ISO 8859-11: ????????? WINSAMI2: ? ? WS2: ? ? macintosh: ?????? Apple Roman: ?????? MacRoman: ?????? windows-1258: ?????? CP1258: ?????? windows-1257: ? ? ??? CP1257: ? ? ??? windows-1256: ???????? CP1256: ???????? windows-1255: ????????? CP1255: ????????? windows-1254: ? ???? CP1254: ? ???? windows-1253: ????????? CP1253: ????????? windows-1252: ? ?? CP1252: ? ?? windows-1251: ????????? CP1251: ????????? windows-1250: CP1250: IBM866: ????????? CP866: ????????? csIBM866: ????????? IBM874: ????????? CP874: ????????? IBM850: ????? CP850: ????? csPC850Multilingual: ????? ISO-8859-16: ? ? ? iso-ir-226: ? ? ? latin10: ? ? ? ISO-8859-14: ????? iso-ir-199: ????? latin8: ????? iso-celtic: ????? ISO-8859-13: ? ? ??? ISO-8859-10: ? ? iso-ir-157: ? ? latin6: ? ? ISO-8859-10:1992: ? ? csISOLatin6: ? ? ISO-8859-9: ?????? iso-ir-148: ?????? latin5: ?????? csISOLatin5: ?????? ISO-8859-8: ????????? ISO 8859-8-I: ????????? iso-ir-138: ????????? hebrew: ????????? csISOLatinHebrew: ????????? ISO-8859-7: ????????? ECMA-118: ????????? greek: ????????? iso-ir-126: ????????? csISOLatinGreek: ????????? ISO-8859-6: ????????? ISO-8859-6-I: ????????? ECMA-114: ????????? ASMO-708: ????????? arabic: ????????? iso-ir-127: ????????? csISOLatinArabic: ????????? ISO-8859-5: ????????? cyrillic: ????????? iso-ir-144: ????????? csISOLatinCyrillic: ????????? ISO-8859-4: ? ? ? latin4: ? ? ? iso-ir-110: ?╣Ŕ?ż?ßÝÚ csISOLatin4: ?╣Ŕ?ż?ßÝÚ ISO-8859-3: ??????ßÝÚ latin3: ??????ßÝÚ iso-ir-109: ??????ßÝÚ csISOLatin3: ??????ßÝÚ ISO-8859-2: ý╣Ŕ°żřßÝÚ latin2: ý╣Ŕ°żřßÝÚ iso-ir-101: ý╣Ŕ°żřßÝÚ csISOLatin2: ý╣Ŕ°żřßÝÚ 

With putty, it clearly works and the correct one is UTF-8. This is what I get when using putty (I cut the rest of the long list):

UTF-8: ěščřžýáíé ISO-8859-1: ?????▒▒▒▒ latin1: ?????▒▒▒▒ CP819: ?????▒▒▒▒ IBM819: ?????▒▒▒▒ iso-ir-100: ?????▒▒▒▒ csISOLatin1: ?????▒▒▒▒ ISO-8859-15: ?▒??▒▒▒▒▒ latin9: ?▒??▒▒▒▒▒ Y~▒▒▒▒LE: Y~▒▒▒▒2BE: 

There may be a problem on the server, but to consider that possibility, I first need to know what encoding does Microsoft Telnet Client actually use. Which encoding is it? Is it saved in some system variable?

1 Answer

Telnet is encoded in ASCII--there is an eight-bit mode that can be negotiated, which is usually used for data transfers.