Logged In: YES 
user_id=143334

refer to the page
http://linux.thai.net/thep/mlit/countries.html

There are only two Thai character encoding standard;
'tis-620' and 'iso-8859-11'. The former is under Thai
Industrial Standards Institute (http://www.tisi.go.th/). You
can see details in
http://www.inet.co.th/cyberclub/trin/thairef/tis620-iso10646.html

The later is under ISO
(http://anubis.dkuug.dk/JTC1/SC2/open/02n3333.pdf).

The both of them refer to code page 874.

There are some non-standard Thai character encoding, refer
to code page 874. These are 'windows-874' 'ibm874'
'x-mac-thai' 'tactis' (adds x-mac-thai and tactis)

The name of Thai character encoding is tis-620 not tis-602
as you mentioned.

Summary:
- 'tis620', 'tis_620', 'ibm874', 'iso_8859_11',
'iso8859_11', 'windows-874', 'x-mac-thai', 'tactis' should
alias to 'cp874'

Additional, I found 'tis260' alias to 'tactis'  in
aliases.py, I sure 'tis260' is typo and 'tactis' is missing.
I suggest remove it.

(please see my update patch)