discount?

It is tricky because this machine is too simple to have an amount discount button. You could void the amount of the coupon off of the department by using the VOID button, or you could program a negative department. Try using void first as that is easiest.
On most models, you can just type 500 VOID then press the department button to remove five dollars from it.
If it doesn't work, then try turning the key to the VOID position and type 500 then the dept button, then payment e.g CASH

Mark
May 2010