Re:Why 56k is the fastest dial up modem speed
by marcus0x62 on Saturday November 25, 2023 @01:56PM
(#38415595)
Sure, with other changes. You would still have to:
* Select (or repair) “good” pairs that didn’t have poor echo, impedance, noise, etc. characteristics.
* Not compand the resulting PCM sample with mu/alaw companding.
* Provide an atomic bearer channel from the telephone switch to the ISP that was at least 112kbps.
* Develop a modem encoding scheme that could take advantage of the extra bandwidth.
At this point, you’ve reinvented a really crappy version of DSL that could be user-signaled to call different networks (i.e., phone numbers.)
The other option, the one that people selected, was to use the copper facilities but bypass the phone switch and its associated audio and in-band signaling shenanigans. That was/is xDSL.
* Select (or repair) “good” pairs that didn’t have poor echo, impedance, noise, etc. characteristics.
* Not compand the resulting PCM sample with mu/alaw companding.
* Provide an atomic bearer channel from the telephone switch to the ISP that was at least 112kbps.
* Develop a modem encoding scheme that could take advantage of the extra bandwidth.
At this point, you’ve reinvented a really crappy version of DSL that could be user-signaled to call different networks (i.e., phone numbers.)
The other option, the one that people selected, was to use the copper facilities but bypass the phone switch and its associated audio and in-band signaling shenanigans. That was/is xDSL.