Does the ICU ISCII convertesr take ATTRIBUTE code in ISCII (as defined in ANNEX-E of ISCII 13194:1991, page 20 to swtich between script?)
ATR = 0xEF in ISCII
0xEF 0x42 to switch to Devanagari script
0xEF 0x43 to switch to Bengali script
etc...
The ICU ISCII converter does handle the script-switching attributes. The default script (before encountering a script attribute) depends on the charset name you use (for example, iscii-dev vs. iscii-guj vs. iscii-tlg or x-iscii-te etc.) or can be set with an ICU-specific option suffix on the ISCII charset name itself.
Search for "ISCII" in http://oss.software.ibm.com/cvs/icu/~checkout~/icu/source/data/mappings/convrtrs.txt
The ICU ISCII converter does not handle non-plain-text attributes like for bold text. (I think it ignores them.)
markus
