A modem handshake visualized

November 19th, 2018 9:49 AM
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Filed under Musings;
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If you're reading this blog, you remember this sound:

Whether your Apple II was dialing into CompuServe, GEnie, Delphi, or a BBS, the sound of two modems connecting heralded something magical: an entry into a world, or a part of the world, where you might find faces and files new and familiar. For many, this cacophonous screech welcomed us to a place we could relax, abandon pretenses, and be ourselves — or whatever version of ourselves we wished to present that day.

The lingo of that connection is nearly lost to me now: 8N1 vs. 7E1, RTS / CTS, full duplex. But almost all of it is represented in that same dial-up soundtrack. Not just an unfortunate and inadvertent consequence of data being modulated and demodulated, the sound of dialup embodies the phases of negotiation before two modems can settle into a digital rapport.

These stages can now be visualized in "The Sound of the Dialup Explained",a 42-megapixel poster crafted by Helsinki's Oona Räisänen. Detailing one point in the poster, she writes on her blog:

[The modems] put their data through a special scrambling formula before transmission to make its power distribution more even and to make sure there are no patterns that are suboptimal for transfer. They listen to each other sending a series of binary 1's and adjust their equalizers to optimally shape the incoming signal. Soon after this, the modem speaker will go silent and data can be put through the connection.

Modem handshake visualization

I can almost hear it.

The poster is available from Redbubble in three sizes, from two to four feet wide.

We may not often hear these sounds anymore — but we can always have this poster to remind us of that raucous gauntlet we'd once endure as passageway into cyberspace.

(Hat tip to Jesse Rebel)