The constraint on computer terminals was inexpensive read-0only memery to hold raster fonts. A set of 72 upper/lower case 5x7 dot letters plus digits and punctu

The constraint on computer terminals was inexpensive read-0only memery to hold raster fonts. A set of 72 upper/lower case 5x7 dot letters plus digits and punctuation is 2520 bits. When half kilobyte ROM chips fell to fifty bucks in the early 1970s then it became economical.