20. This screen shot again shows the Open Bands Boxes that appear on the Main Screen and Circuit Analysis Screen. A green box shows that the band is "open" at current time. "Open" is defined as a predicted SNR value that is at or above the Required SNR level for the specified Service Type at the Required Reliability. The colors track any circuit changes you make. Red boxes show "closed" circuits; yellow means a marginal condition. The box colors update every five minutes. The numbers under the boxes show the current user frequency settings for each band. The Main and Circuit Analysis screens also have a station "ID Timer"--a small digital clock that may be started when an on-air session is begun and turns red every 10 minutes as a reminder to give a station ID announcement. It is common practice to have an ACE-HF screen "up" during station operation. Glancing at the Open Bands Boxes and noting the ID timer status can greatly enhance the ham experience.