Hi Pete ,
to use the stepper drivers you will need to either convert the 5V TTL logic signals from your breakout board / printerport
to 24v levels as used by industrial controllers
or modify the stepper drivers to the 5v input version by changing a few resistors
to avoid modding the stepper drivers
you will need to use either a TTL logic IC with a open collector output like the 7407 or transistor array like the ULN2803
http://www.cedmagic.com/tech-info/data/7407.pdfhttp://www.datasheetcatalog.org/datasheets/90/366828_DS.pdfof the two IC's, the ULN2803 will be the easiest use on a piece of veroboard (perf board)
as all the inputs are on one side and the outputs on the other
with a +24V supply connected to the drivers + step ,+dir and +enable inputs
using a ULN2803 ,the +5V TTL logic outputs from your breakout board will be able to switch the drivers - step , -dir and -enable inputs to ground
when a breakout board output is at 0v the ULN2803 output will be switched off and no current will flow through the LED in the stepper drivers input optoisolator
it will be possible to modify your drivers if you had the circuit diagram or traced the connection to the optoisolators
for each input you will need to change the resistors that limit the LED current
for 5V inputs the resistor will be about 220 to 330 ohms
John