| Syst. of laws |
| Syst. of unspoken words |
| Data-sharing syst. |
| Soundless communication syst. |
| Syst. |
| Nonverbal syst. |
| Communication syst. for the hearing-impaired |
| Computer syst. |
| Raytheon syst. |
| Communication syst. with hand signals |
| Metric measurement syst. |
| Broadcasting syst. |
| Handmade syst.? |
| Blood-typing syst. |
| Syst. with gestures |
| Handmade communication syst.? |
| Handy communication syst.? |
| Defense syst. |
| Syst. for the hearing-impaired |
| Syst. of measurement |
| Silent communication syst. |
| Google Earth mapping syst. |
| Syst. with hand signals |
| Increased-clarity syst. |
| Life support syst.? |
| Syst. first implemented during W.W. I |
| Spring forward, fall back" syst. |
| Schedule-shifting syst. |
| Dactylology syst. |
| Blood type syst. |