Where they come from
Each shul chooses once, under Settings, below the address, in Where zmanim come from:
- Chabad.org's published times, the usual choice: Chabad.org's own luach for the shul's address, a month ahead. They follow the Baal HaTanya, and are shown exactly as Chabad.org publishes them, to the minute, under its own names.
- Hebcal: the times worked out for the shul's address, with every shitah to choose from in the Zmanim item. With Hebcal, set Candle lighting (how many minutes before sunset; most shuls use 18, Jerusalem 40) and Shabbos and Yom Tov end (three small stars, three medium stars, 72 minutes, or a set number of minutes after sunset).
Each choice shows the coming Friday's candle lighting, so you can check it against the shul's luach before choosing. A change reaches the screens within a minute.
Both are kept on each TV months ahead, so a dropped connection doesn't blank them. The Zmanim item says under it where its times came from: "Zmanim from Chabad.org", "Zmanim from Hebcal", or both.
The shul's address
Set it under Settings. For a shul in the US, the address's ZIP code is what Chabad.org's times are fetched for. For a shul anywhere else, choose the nearest city from the list that appears. The time zone comes from the address too, and Hebcal works its times out from the address itself.
Which zmanim show
In the Zmanim item's Content, tick the Times to show; they're listed in the order of the day. Show all of them, or only the Next one. Under More options, When it doesn't fit chooses scrolling, paging or shrinking.
With Hebcal, a zman with more than one shitah is a group, its opinions under it: Dawn (Alos), Latest Shema, Latest Shacharis and Nightfall (Tzeis). Tick two opinions of the same zman and the board names each one, like "Latest Shema (Magen Avraham)"; with one, the board shows just the zman's name. With Chabad.org's times, the shitos it doesn't publish are under Other shitos, greyed, with the way to them: choose Hebcal.
Nightfall on Shabbos and Yom Tov shows when Shabbos or Yom Tov ends, under its own name.
Names in Hebrew
Language in the item's Content shows the names in English, Hebrew or Transliterated Hebrew. In Hebrew the names are the luach's own, like עלות השחר, הנץ החמה, סוף זמן קריאת שמע and שקיעת החמה, and the table reads right to left: names on the right, times on the left. Each time still reads "7:22 PM".
A day Chabad.org hasn't published yet
On Chabad.org's times, a date or a zman Chabad.org hasn't published yet (further ahead than the month it's fetched for, or a fetch that didn't work) shows Hebcal's time, worked out the way Chabad.org does: the Baal HaTanya, candle lighting 18 minutes before sunset, Shabbos ends at 8.5°. A screen shows it like any other time. Only the editor says so, on the item and in its panel, until Chabad.org's own time arrives and takes its place. Fetching is tried again within the hour.
Without an address, there are no zmanim at all; the editor asks for one, and a screen shows nothing there. See Troubleshooting.
The Jewish calendar
The Hebrew date, the parsha, Daf Yomi, Sefiras HaOmer and Shabbos Mevarchim are worked out on the TV itself, from the date. They don't need the internet at all.