These are all the possible values for the IG_ISIS_TAG_FEEDORDER tag.
Values:
| IG_ISIS_FEED_SIMPLEX_1_TO_N | Scan front 1 to n. |
| IG_ISIS_FEED_SIMPLEX_N_TO_1 | Scan front n to 1. |
| IG_ISIS_SCANTYPE_FEEDER_REVERSING | Scan front and page is in reverse order. |
| IG_ISIS_SCANTYPE_DUPLEX_REVERSING | Scan both sides and page is in reverse order. |