Analysis of information sources in references of the Wikipedia article "Commodore bus" in English language version.
Output Low Current (Sinking); VOL < .4 v (PA0-PA7, PC, PB0-PB7, DB0-DB7) IOL 3.2 mA
Programming tricks used by Epyx have yielded transfer rates of up to 2.5 kilobytes per second.
The 1541 works with the Plus/4 just fine.
(1) 6' or 1.8 meters (max) 4 conductor shielded cable (for serial connection)
Output Low Current (Sinking); VOL < .4 v (PA0-PA7, PC, PB0-PB7, DB0-DB7) IOL 3.2 mA
Programming tricks used by Epyx have yielded transfer rates of up to 2.5 kilobytes per second.