Because the ANCD replaces the paper Signal Operating Instructions (SOI), the operator performs this task whenever SOI information on nets, suffixes, pyrotechnics, smoke, or sign/countersign is required. As many as 40 Quick Reference (QREF) items can be made available to the operator in list form. Full SOI information is readily available for all QREF entries. Up to five time periods (24-hour days) may be included in each QREF file.