IBM 2741 definition printer
A slow, letter-quality printing device and terminal
based on the IBM Selectric typewriter
. The print head was a little sphere resembling a golf ball, bearing reversed embossed images of 88 different characters arranged on four parallels of latitude; one could change the font by changing the golf ball. The device communicated at 134.5 bits per second, half duplex
. When the computer transmitted, it physically locked the keyboard.
This was the technology that enabled APL
to use a non-EBCDIC
, and in fact completely non-standard character set
. This put it 10 years ahead of its time - where it stayed, firmly rooted, for the next 20, until character displays gave way to programmable bit-mapped
devices with the flexibility to support other character sets.