101–110 of 143 posts
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This did happen eventually. In the late 90's, various companies (Cisco, Ascend) provided boxes that could handle 24 modems on a single T1 port (PRI or channelized T1.) This massively improved ISP port density. Before that, it was racks and racks of modems...
IIRC it was the only way to support 56k.
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Modern cellphone networks support wideband codecs, e.g. AMR-WB.
Is that working across networks, though?
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That 128Kbps on ISDN was the like the gold standard back then! I knew some sysadmins who had that installed to their homes so they could be available at any time. All paid for by the company they worked for.
The most bang for buck "employee benefit" I ever offered to my guys back in the earl 00's was a T1 line to their home for free. We could do this since local loops to most folks were about $150-200/mo, and we already had a channelized DS3 terminated at our rack at a local datacenter for our phone banks. If you bought your own DS1 retail you'd be paying upwards of $1k/mo back then to a provider. It was by far the best…
Yes these modems were almost-ISDN (minus the razor fast call setup). And required a full digital backend to work. They could only do 56k6 in one direction, to the user too. But they were made for internet access so that didn't really matter.
I remember my brothers friend in rural Portugal having one way satellite Internet back in the 90s to very early 00s - you used a standard dial up for the upstream, but with a satellite dish got much much faster downloads. Blew my mind that you could go out one way and receive another and still get a functioning (and fast) connection.
It was cool having a fast downstream but the slow upstream over finicky dial-up was a pain in the ass. If the dial-up dropped the in progress downloads all died because no ACKs could be sent. Gaming was no better than plain dial-up since your upstream had the same shitty latency as plain dial-up.
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I think it was ubiquitous. NPR in the 90s and 2000s used ISDN to allow many of their commentators to work from home. I think where you hear those crazy 8KHz clipped calls is where it's not an option. Mostly these days remote radio and podcast interviews I hear remote participants sound more like they're on mobile phones: variable voice quality with an almost unbearable latency.
Every once in awhile the stars align and I randomly get an "HD" voice call. It's disorienting to both me and the other party how good the quality is.
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Every once in awhile the stars align and I randomly get an "HD" voice call. It's disorienting to both me and the other party how good the quality is.
It is the reason why we switched to using FaceTime audio. The sound quality is so much better than over the normal voice line. I don’t know how to reliably get HD Voice.
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Yes, the Intelligent Network was the big thing in the 1990s. It allowed for routing as you describe as well as calling cards and many other features: https://en.m.wikipedia.org/wiki/Intelligent_Network
Oh the joys of watching terminal logs with SS7 data frames!
We’ve had techs come to our home in Canada in the 1990s, and I remember being fascinated with their mystical toolbox phone that seemed to uncover hidden phone line functionality. Almost like the whip in Indiana Jones.
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192 kHz is the sampling rate, not the sound frequency.
nyquist-shannon means that you only need to sample at 192khz if you need to encode signals up to 96khz. humans can’t hear above 20khz. adult humans can’t hear above 16khz or so, we lose the top end before age 20. this means that the standard 48khz sampling rate covers the entire human hearing range and then some (0-24khz). any sampling rate over 48khz for sound intended for human hearing is a total waste.
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nyquist-shannon means that you only need to sample at 192khz if you need to encode signals up to 96khz. humans can’t hear above 20khz. adult humans can’t hear above 16khz or so, we lose the top end before age 20. this means that the standard 48khz sampling rate covers the entire human hearing range and then some (0-24khz). any sampling rate over 48khz for sound intended for human hearing is a total waste.
Why do 96 or 128khz sampled audio files sound better than 48khz ones? I blind tested and could always tell the difference between them, but not between 128 and 192
Also, you might possibly be sensitive to resampling artifacts if your output device runs at 44.1kHz and your file is 48kHz or vice versa.
Audio testing is hard, and testing on yourself is tricky... But if you have a sample that you're convinced sounds better at high rates than lower rates, I would urge you to put it through a tool to resample it down to lower rates and see if/when you can tell the difference. If the rate isn't an even multiple, it's worth using a tool that can dither; dithered resampling artifacts are less abrasive than undithered... I had some voice recordings to play over the phone, and everything needed to be 8kHz u-law; the 48kHz original recordings sounded better than 44.1kHz original recordings because one is even multiple and the other isn't, but either way, the waveforms looked worse than it sounded.
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Oh the joys of watching terminal logs with SS7 data frames!
Was there any way for the customer to somehow interact with SS7 frames? We’ve had techs come to our home in Canada in the 1990s, and I remember being fascinated with their mystical toolbox phone that seemed to uncover hidden phone line functionality. Almost like the whip in Indiana Jones.