Check out Mr. Fancy T1 line over here. I remember downloading Slackware floppy images over 28.8 dialup. Talk about pain. I recently stumbled on a dusty box of them whilst cleaning out the attic.
2400 baud. I wish. I had to manually dial my rotary phone and then place the handset into my 300 baud CAT acoustic coupler modem.
To be fair by the time I 1st used Slackware that 300 baud modem had long been replaced and I at the time I had bonded ISDN channels for 128kbs connection paid for by my employer. Soon replaced by a T1 to my home also paid for by my employer.
Did you employer give you a spec-'d out computer/workstation too? I don't even know how you hook up ISDN equipment, but I know an SGI Indy had it built in.. ~1993.
I'm thankful I never experienced that. My family switched from AOL dial up to an AT&T ADSL connection (either started out as 128, 256 or 512kbps down circa 2006 IIRC). It still didn't make downloading FreeBSD and Fedora Core 6 ISOs easy but it definitely was doable in a reasonable amount of time!
Do you remember the dreaded 'floppy disk is probably unreadable' sound during installation of any software on floppy?