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  • Re: Serial Port: YouTube over Dialup

    From Bob Worm@21:1/205 to poindexter FORTRAN on Sat Oct 18 19:32:12 2025
    Re: Re: Serial Port: YouTube over Dialup
    By: poindexter FORTRAN to Bob Worm on Fri Oct 17 2025 16:52:51

    Hi, pF.

    European E1 did have 30 channels. I got my circuits crossed (ahem...) straight T1 gave you 24 56kb/channel, using robbed-bit signalling.

    The worst of both worlds, if you like :) That's interesting, because over here if you used an E1 for primary rate ISDN you got 30x64K plus separate signalling, it was often called "an ISDN 30". How does it work if you use a T1 for terminating ISDN calls (assuming you can / could)?

    ISDN here was 2x64kb/1x8kb, but when you hooked up a 56k modem, you'd have a pretty good chance of getting a fast connect, because your half of the circuit was all digital. I got lots of 56K and 53K connects running that way.

    Now this is the bit I never got to play with but I understood that getting dial up to connect above 33k6 required ISDN at the provider end. I guess they'd only let you signal up a voice call, though, not data so you couldn't get ISDN end-to-end.

    ISDN was great back in the day. I wish they'd rolled it out in place of dial up over POTS. Instead what we got was "Home Highway" which was residential ISDN, marketed as "midband". That went precisely as far as you'd imagine when most people could get ADSL at that time.

    BobW
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  • From poindexter FORTRAN@21:4/122 to Bob Worm on Sat Oct 18 15:12:30 2025
    Re: Re: Serial Port: YouTube over Dialup
    By: Bob Worm to poindexter FORTRAN on Sat Oct 18 2025 07:32 pm

    The worst of both worlds, if you like :) That's interesting, because over here if you used an E1 for primary rate ISDN you got 30x64K plus separate signalling, it was often called "an ISDN 30". How does it work if you use a T1 for terminating ISDN calls (assuming you can / could)?

    You could - ISDN Primary Rate Interface was 23 64K channels plus a 8k D channel. we used Ascend Pipeline routers that'd bring in a PRI on one side and accept connections from users with BRI lines on available channels - then route them to our network.
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  • From Bob Worm@21:1/205 to poindexter FORTRAN on Mon Oct 20 11:38:09 2025
    Re: Re: Serial Port: YouTube over Dialup
    By: poindexter FORTRAN to Bob Worm on Sat Oct 18 2025 15:12:30

    Hi, pF.

    You could - ISDN Primary Rate Interface was 23 64K channels plus a 8k D channel. we used Ascend Pipeline routers that'd bring in a PRI on one side and accept connections from users with BRI lines on available channels - then route them to our network.

    Thanks for the explanation - every day's a school day and it's always more interesting to get a real life answer than to look it up on Wikipedia (no offence to Wikipedia, I love that site).

    I'm surprised the PRI's D channel was only 8k - seems like having the same size D channel for a BRI with two bearers vs. 23 would be a bit generous. My memory has disappeared down the time tunnel a bit but I thought European PRI were 30 x 64k B channels + 2 x 64k D channels to make it up to 2048k. Maybe you need to lose some for framing *shrug*. Come to think of it, I could have sworn BRI had a 16k D channel?

    I met up with some of the (other) old fogies from my time in Alcatel-Lucent the other week, maybe the next time I see them I'll bring up TDM and watch their eyes light up...

    BobW
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