Ode to Internet – V.90 56k dialup modem handshake for orchestra (1996) [video]

There's an interesting reason for that. A digital modulation that is going fast enough, if it is well-designed to make use of a channel, will approximate white noise. A primary frequency or harmonic can be thought of like a "hot spot" and the more relatively powerful it is, the more it will distort the other frequencies. So, an ideal encoding will have constant average power across the entire bandwidth. Essentially, white noise.

Modems got there by the late 1980s with the jump to 9600 bps, when a single bit started being spread out over many symbols using convolutional modulation.

Depends which 56K “standard” you are using. There were two before v90 standardised things, they had different handshake modifications for negotiating the faster link, and v90 was different again. Some ISPs supported only one of the earlier “standards” for some time after v90 (most v90 modems were firmware switchable between it and one of the older methods or were soft-modems where that switch was in the driver).

My understanding is that it required digital equipment at the exchange end which would make it impossible to do with two standard modems wired back to back. Unless someone has some telco kit laying around, it might be a lost sound.

Your critique falls flat (pun intended) because there is no DTMF here.

Also, this video is a chopped-up edit from a session of real music performance, rather than someone's original composition. Many commenters seem oblivious to this distinction.

Twitter, Reddit and HN can sometimes be pretty loud.