TUI using slang with pure ascii (7 bit) characters via termcap

Question

I am using newt/snack (a TUI graphical Widgit library for Python based on slang) to have some interactive scripts. However for some target terminals the output of those screens are not very nice. I can change the look of them by changing the $TERM variable to remove non printable characters, and to convert them to something more suitable. For example:

TERM=linux python myscript.py

So far the values I tested for $TERM, yielded only moderate success.

Is there a known value for $TERM that consistently converts graphical characters:

┌────────────┤ Title ├────────────┐
│                                 │
│ Some text for the entry window  │
│                                 │
│   foo _______________________   │
│   bar _______________________   │
│   baz _______________________   │
│                                 │
│    ┌────┐        ┌────────┐     │
│    │ Ok │        │ Cancel │     │
│    └────┘        └────────┘     │
│                                 │
└─────────────────────────────────┘

into non graphical characters:

+------------| Title |------------+
|                                 |
| Some text for the entry window  |
|                                 |
|   foo _______________________   |
|   bar _______________________   |
|   baz _______________________   |
|                                 |
|    +----+        +--------+     |
|    | Ok |        | Cancel |     |
|    +----+        +--------+     |
|                                 |
+---------------------------------+