Internet Teletype · Listener Maps
Four views of who is listening to ITTY, and what each one is actually telling you. Start with the pin — everything else follows from it.
First principle
ITTY only ever learns a listener's IP address. A lookup service turns that into a city, and the pin sits at the city's centre point — not at anybody's house. Two people in the same town share one pin.
Before grouping, coordinates are rounded to about 1.1 km. That sounds fussy, but without it the same place comes back at slightly different numbers on different days and draws two pins stacked exactly on top of each other — which is how the map once reported eleven listeners where you could only count ten.
Precise to the pixel, not to the listener.
How every page works
All four views work the same way underneath, and it is simpler than it looks. When you open the page, it runs one batch of database queries, hands the results to your browser, and the browser draws the map from there.
That is the whole cycle. Nothing updates in the background, nothing is fetched as you pan or zoom, and no view ever polls for news. What you are looking at is a snapshot from the moment the page loaded. Reloading is the only way to get fresh data.
It also means filtering is instant: the page already holds every point it could possibly show you, so hiding a channel is just a redraw.
The four views
| View | Answers | Covers |
|---|---|---|
| Live | Who is listening right now? | The last five minutes |
| Last 7 Days | Who has been listening lately? | A rolling week |
| All-Time | Where has ITTY ever been heard? | Everything since 24 July 2026 |
| Time-Lapse | How has listening changed? | The same span, animated |
listeners_map.php
The collector checks all four streams every five minutes, throws away the previous list and writes a fresh one. This map draws that list.
So it is never more than five minutes behind — and never less than zero minutes behind either.
The legend counts connections, which is not the same as the number of pins. One household can hold four streams open at once; when that happens the listener list marks it (x4).
Reads the current snapshot
listeners_map_7days.php
Not really a separate map. It is the All-Time page with the window cut to a week — same code, same shading, same everything.
This is the one to use when you want to know who is actually around. Places that have gone quiet drop off it completely, which is exactly what the All-Time map will never do.
Reads the last seven days
listeners_map_alltime.php
Every place that has ever appeared, all at once. A historical record, not a live view — nobody on it is necessarily listening now.
Brightness means recency. A bright solid pin was heard just now; a faint ghost has not been heard in a long time. It is measured against the newest moment in the data, not against your computer's clock, so a quiet spell can't wash out the whole map.
The legend here counts pins — places, not connections.
Reads the whole record
listeners_map_timelapse.php
The same history played as an animation. Every five-minute check is one frame; press play and watch pins appear and vanish over weeks. There is a scrubber and speeds from 4× to 64×.
It will not send your browser more than 2,000 frames. The full span is past 7,400, so it currently keeps every fourth one and says so on screen: 1 poll in 4, about twenty minutes a frame. Narrow the dates and you get every frame back.
Reads the whole record, as frames
On every map
Every legend row is a tick-box. Untick a channel and the map hides places that aren't on anything you've kept, and dims the unlit corners on the pins that remain. Three things are worth knowing:
It shows anything, not everything. A place stays visible if it is on any channel you've kept ticked — not only if it's on all of them.
The legend numbers don't move. Each one is that channel's own total; unticked rows just go grey. The pin counts, the pop-ups and the listener lists do narrow to what you've selected.
You can't untick the last one. An empty map should always mean "nobody was listening" — never "you filtered everything away".
Your selection travels with you. Switch views and the filter comes along, and the address bar carries it too, so a filtered map is a link you can send to somebody.
Read with care
The current-listener list is only ever overwritten, never cleared. If the collector stops, the list sits there holding whoever was connected at the last successful check, and the page keeps serving it quite happily. If the same people have been on for hours without moving, treat it with suspicion.
The Live legend counts connections; the All-Time legend counts pins. Ten connections from seven places is not a miscount — it usually means somebody's player has left spare streams open. Open the listener list and look for an (x4).
A place that has gone quiet fades to a faint ghost and stops there. It does not vanish, and it keeps counting in the legend for good. That is deliberate — a footprint map that forgot places would just be a slower Live map. For who is genuinely active, use Last 7 Days.
Over a long range it drops frames to stay quick, and a listener who came and went inside a single skipped gap never appears at all. The note under the title always tells you the current step. If you are studying a particular day, set the dates and watch it at full detail.
ITTY streams MP3 audio carrying Baudot RTTY tones; a sound-card modem decodes
it and drives a real teleprinter. The maps show where those machines are.
Listener positions are city-level only. Coverage begins 24 July 2026.