I believe Optimum Tech's build is wrong (0.25-slot offset)

t1 slotThe first time slot is numbered 1. For a T1 controller, the time slot range is from 1 to 24. For an E1 controller, the time slot range is from 1 to 31. unframed—Unframed modeslotport: 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,