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.
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.