Box Drawing

Block from U+2500 to U+257F. This block was introduced in Unicode version 1.1 (1993). It contains 128 codepoints.

The Wikipedia provides the following information on block Box Drawing:

Box Drawing is a Unicode block containing characters for compatibility with legacy graphics standards that contained characters for making bordered charts and tables, i.e. box-drawing characters.

Chart at Unicode.org (PDF)
Block at Decode Unicode