t1 slotBuild flexibility goes a long way with 2-slot and 3-slot mode for the T1. Here I managed to fit a Zotac RTX 3070 Twin Edge with ease. ... The T1 is definitely one of the mostslotport: Slot number and port number where the channelized E1 or T1 controller is located. number : Channelized E1 or T1 controller number. timeslots: For ISDN, the D channel timeslot,