Hi Marcus, there are two different types of "codes" that are used to enter a repeater and other uses. One referred to as "PL" (private-line), or (ctcss) continuous tone coded squelch system. These are analog sub-audible tones. You have a choice of about 38 of them. Then you have have the same concept except they are "DPL", digital coded sub-audible. They both do the same job....you just need to know the code required to use the repeater. The program instructions should allow you to enter the required one!
I hope this explanation helped you in some way.
Regards,
David
WRHT835