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A few years back I realized I had a non-used landline due to DSL and I thought it would be fun to try to log into every BBS remaining in the country. I picked u

by nullc 3y ago

A few years back I realized I had a non-used landline due to DSL and I thought it would be fun to try to log into every BBS remaining in the country. I picked up a nice external courier modem from weird stuff for a couple dollars and started dialing. I was thwarted by two factors, one is that the vast majority of the numbers I could find were now answered by humans who I felt bad for bothering. The other was the apparently even a lot of landlines (including my own) have VoIP steps in their transport that modem traffic doesn't work well across.

tjohns 3y ago
Now I'm wondering: 1) Can you get a digital line to support 56k BBS hosting anymore? 2) Can you even get an analog copper line from AT&T for outbound calling? (I know the FCC recently said carriers aren't required to offer it anymore.) 3) Absent either of the above, what's the best speed you can reliably do over VoIP, assuming G.711 / no compression?
- nullc 3y ago
  So I found the modem unreliable even with it constrained to lower speeds. I don't recall what I used, but I'd WAG it was V.32 (9600 bps) as that's the lowest speed that still has forward error correction (and also happens to be fast enough to be reasonable to use). Maybe I also tried 1200? Not sure, as mentioned I also had the issue of accidentally harassing people. I think in general the issue is that there is a jitter buffer and async clocking that causes timing slips that upset the modem. A sufficiently advanced(tm) demodulator could presumably handle it, but I can't control the remote side... There is a lot of text out there on getting fax to work right, but there are options for fax that don't apply to the general case of modems. Very very few BBSes were _ever_ 56k. V.90 eliminates the extra low resolution A->D stage from the provider to the user by having the provider connect digitally (via ISDN PRI or T1). So in the downstream direction the only A->D stage is in the users modem and can be higher resolution, so all codewords are reachable. 33.6k BBSes and 28.8k (including in the async HST form) were certainly a thing. By the time technology for 56k was available (1998?) we were well into the internet access age, and the monthly cost for a PRI or T1 was well out of budget for all except the largest BBSes (many of which were transitioning or had transitioned to be ISPs by that point in any case).

by nullc 3y ago

tjohns 3y ago

Now I'm wondering: 1) Can you get a digital line to support 56k BBS hosting anymore? 2) Can you even get an analog copper line from AT&T for outbound calling? (I know the FCC recently said carriers aren't required to offer it anymore.) 3) Absent either of the above, what's the best speed you can reliably do over VoIP, assuming G.711 / no compression?

nullc 3y ago
So I found the modem unreliable even with it constrained to lower speeds. I don't recall what I used, but I'd WAG it was V.32 (9600 bps) as that's the lowest speed that still has forward error correction (and also happens to be fast enough to be reasonable to use). Maybe I also tried 1200? Not sure, as mentioned I also had the issue of accidentally harassing people. I think in general the issue is that there is a jitter buffer and async clocking that causes timing slips that upset the modem. A sufficiently advanced(tm) demodulator could presumably handle it, but I can't control the remote side... There is a lot of text out there on getting fax to work right, but there are options for fax that don't apply to the general case of modems. Very very few BBSes were _ever_ 56k. V.90 eliminates the extra low resolution A->D stage from the provider to the user by having the provider connect digitally (via ISDN PRI or T1). So in the downstream direction the only A->D stage is in the users modem and can be higher resolution, so all codewords are reachable. 33.6k BBSes and 28.8k (including in the async HST form) were certainly a thing. By the time technology for 56k was available (1998?) we were well into the internet access age, and the monthly cost for a PRI or T1 was well out of budget for all except the largest BBSes (many of which were transitioning or had transitioned to be ISPs by that point in any case).