Epson MX-80 User Manual page 84

Appendix C
Using the MX-80 With a Standard Radio Shack Cable
There is a difference between the 'official' EPSON printer cable and the ones
supplied by Radio Shack. They are wired slightly differently.
The EPSON cable allows separation of the CR(carriage return) and the LF(line
feed) commands. This in turn allows such things as underlining, overstrikes to
slash zeros, sevens, the letter Z, to "black o u t " material, etc.
If you do not need to separate CR and LF and already have a Radio Shack printer
cable, it should work fine. If purchasing a new cable, buy an EPSON to keep all
your options open.