[vel0city]

G.711, the standard encoding for home phone systems since they went digital, is usually filtered at 300–3400Hz as well. Chances are if you had a home phone in the 80s or 90s it was filtered at 300-3400Hz somewhere along the path.

[lxgr]

And the history of that filtering even predates digital lines, due to frequency multiplexing: https://en.wikipedia.org/wiki/L-carrier