 Initiated as a more suitable replacement for the Portable, the only features the first generation 170 did not include in its reduced space were an external video port and internal ROM and PDS expansion slots.Indeed, Apple canceled its own external monitor adapter for the Portable shortly after it was announced, instead relying on numerous third party providers for solutions (still applicable to the 170) and FCC regulations of the day prevented any real use of the PDS expansion slot, by restricting any external connections to it.The PowerBook 180 replacement would address external video less than a year later, but expansion slots would not return to Macintosh portables until three years later with the PowerBook 500 series, in the form of PCMCIA cards.