rj45 to serial 25 pin for serial printers on j2 aures elo micros par and some other brands etc epos systems other brands use different models
simply plug in your rj45 cable to your serial port and this and setup your printer in your softare com port and speed and you are done
par m5100
j2 615 580 etc
Micros workstation 5 6 4 5a (the serial port numbers will be labelled wrong)
posiflex and others are wired differently