Custom Encoding Tables

To create your own encoding table, choose exactly 64 unique ASCII characters (i.e.: no character can be used more than once). Enter these in the Custom Encoding Table section of Configure Attachments....

When using custom encoding tables, a "table" line will be added, followed by two 32 character lines representing your custom table. The standard "begin" and encoded data will follow.

Custom Encoding Tables are discouraged in the MIME standard and are only needed when an attachment is failing to pass through a particular gateway when using Base64, UU or XX encoding, or if you are particularly eccentric.

Be warned that not all decoders support custom-tables, so the further you deviate from common encoding standards, the less likely that the general population will be able to decode your attachments.

This type of encoding is rarely used these days.